Upgrade rspec-rails to 3.8.2 and dependencies

This brings the rspec-core version in line with the Gitaly changes
and introduces Rails 5.1/5.2 improvements.

Full CHANGELOG:
https://github.com/rspec/rspec-rails/blob/master/Changelog.md

Gemfile

@@ -339,7 +339,7 @@ group :development, :test do
   gem 'database_cleaner', '~> 1.7.0'
   gem 'factory_bot_rails', '~> 4.8.2'
-  gem 'rspec-rails', '~> 3.7.0'
+  gem 'rspec-rails', '~> 3.8.0'
   gem 'rspec-retry', '~> 0.6.1'
   gem 'rspec_profiling', '~> 0.0.5'
   gem 'rspec-set', '~> 0.1.3'

Gemfile.lock

@@ -783,36 +783,36 @@ GEM
       chunky_png
     rqrcode-rails3 (0.1.7)
       rqrcode (>= 0.4.2)
-    rspec (3.7.0)
-      rspec-core (~> 3.7.0)
-      rspec-expectations (~> 3.7.0)
-      rspec-mocks (~> 3.7.0)
-    rspec-core (3.7.1)
-      rspec-support (~> 3.7.0)
-    rspec-expectations (3.7.0)
+    rspec (3.8.0)
+      rspec-core (~> 3.8.0)
+      rspec-expectations (~> 3.8.0)
+      rspec-mocks (~> 3.8.0)
+    rspec-core (3.8.2)
+      rspec-support (~> 3.8.0)
+    rspec-expectations (3.8.4)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.7.0)
-    rspec-mocks (3.7.0)
+      rspec-support (~> 3.8.0)
+    rspec-mocks (3.8.1)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.7.0)
+      rspec-support (~> 3.8.0)
     rspec-parameterized (0.4.2)
       binding_ninja (>= 0.2.3)
       parser
       proc_to_ast
       rspec (>= 2.13, < 4)
       unparser
-    rspec-rails (3.7.2)
+    rspec-rails (3.8.2)
       actionpack (>= 3.0)
       activesupport (>= 3.0)
       railties (>= 3.0)
-      rspec-core (~> 3.7.0)
-      rspec-expectations (~> 3.7.0)
-      rspec-mocks (~> 3.7.0)
-      rspec-support (~> 3.7.0)
+      rspec-core (~> 3.8.0)
+      rspec-expectations (~> 3.8.0)
+      rspec-mocks (~> 3.8.0)
+      rspec-support (~> 3.8.0)
     rspec-retry (0.6.1)
       rspec-core (> 3.3)
     rspec-set (0.1.3)
-    rspec-support (3.7.1)
+    rspec-support (3.8.2)
     rspec_junit_formatter (0.4.1)
       rspec-core (>= 2, < 4, != 2.12.0)
     rspec_profiling (0.0.5)
@@ -1212,7 +1212,7 @@ DEPENDENCIES
   rouge (~> 3.5)
   rqrcode-rails3 (~> 0.1.7)
   rspec-parameterized
-  rspec-rails (~> 3.7.0)
+  rspec-rails (~> 3.8.0)
   rspec-retry (~> 0.6.1)
   rspec-set (~> 0.1.3)
   rspec_junit_formatter

spec/models/repository_spec.rb

@@ -2426,16 +2426,15 @@ describe Repository do
       # Gets the commit oid, and warms the cache
       oid = project.commit.id
-      expect(Gitlab::Git::Commit).not_to receive(:find).once
-      project.commit_by(oid: oid)
+      expect(Gitlab::Git::Commit).to receive(:find).once
+      2.times { project.commit_by(oid: oid) }
     end
     it 'caches nil values' do
       expect(Gitlab::Git::Commit).to receive(:find).once
-      project.commit_by(oid: '1' * 40)
-      project.commit_by(oid: '1' * 40)
+      2.times { project.commit_by(oid: '1' * 40) }
     end
   end

spec/services/issuable/bulk_update_service_spec.rb

@@ -165,7 +165,7 @@ describe Issuable::BulkUpdateService do
       context 'when the new assignee ID is not present' do
         it 'does not unassign' do
           expect { bulk_update(issue, assignee_ids: []) }
-            .not_to change { issue.reload.assignees }
+            .not_to change(issue.assignees, :count)
         end
       end
     end

spec/services/merge_requests/mergeability_check_service_spec.rb

@@ -11,7 +11,11 @@ describe MergeRequests::MergeabilityCheckService do
     end
     it 'does not change the merge ref HEAD' do
-      expect { subject }.not_to change(merge_request, :merge_ref_head)
+      merge_ref_head = merge_request.merge_ref_head
+
+      subject
+
+      expect(merge_request.reload.merge_ref_head).to eq merge_ref_head
     end
     it 'returns ServiceResponse.error' do
@@ -73,7 +77,7 @@ describe MergeRequests::MergeabilityCheckService do
       it 'second call does not change the merge-ref' do
         expect { subject }.to change(merge_request, :merge_ref_head).from(nil)
-        expect { subject }.not_to change(merge_request, :merge_ref_head)
+        expect { subject }.not_to change(merge_request.merge_ref_head, :id)
       end
     end

spec/services/merge_requests/update_service_spec.rb

@@ -598,7 +598,7 @@ describe MergeRequests::UpdateService, :mailer do
             feature_visibility_attr = :"#{merge_request.model_name.plural}_access_level"
             project.project_feature.update_attribute(feature_visibility_attr, ProjectFeature::PRIVATE)
-            expect { update_merge_request(assignee_ids: [assignee]) }.not_to change { merge_request.reload.assignees }
+            expect { update_merge_request(assignee_ids: [assignee]) }.not_to change(merge_request.assignees, :count)
           end
         end
       end