corrected a few warnings

lib/gitlab/import_export/importer.rb

@@ -7,7 +7,7 @@ module Gitlab
         new(*args).import
       end
-      def initialize(archive_file: , shared:)
+      def initialize(archive_file:, shared:)
         @archive_file = archive_file
         @shared = shared
       end

lib/gitlab/import_export/project_tree_restorer.rb

@@ -73,7 +73,7 @@ module Gitlab
           relation.values.flatten.each do |sub_relation|
             if sub_relation.is_a?(Hash)
-              relation_hash =  relation_item[sub_relation.keys.first.to_s]
+              relation_hash = relation_item[sub_relation.keys.first.to_s]
               sub_relation = sub_relation.keys.first
             else
               relation_hash = relation_item[sub_relation.to_s]

lib/gitlab/import_export/repo_restorer.rb

@@ -11,7 +11,7 @@ module Gitlab
       end
       def restore
-        return false unless File.exists?(@path_to_bundle) || wiki?
+        return false unless File.exist?(@path_to_bundle) || wiki?
         FileUtils.mkdir_p(path_to_repo)