Make SCSS lint and RuboCop happy

app/assets/stylesheets/pages/merge_conflicts.scss

@@ -8,7 +8,7 @@ $origin_gutter:           #e0f0ff;
 $selected_origin_gutter:  #a3d3ff;
 $selected_origin_line:    #cee4f9;
-$unselected_gutter:       #eeeeee;
+$unselected_gutter:       #eee;
 $unselected_line:         #f8f8f8;
@@ -93,8 +93,8 @@ $unselected_line:         #f8f8f8;
     button {
       border-radius: 4px;
-      border: 1px solid #E1E1E1;
-      background: #FFF;
+      border: 1px solid #e1e1e1;
+      background: #fff;
       font-size: 10px;
       position: absolute;
       right: 20px;

app/controllers/projects/merge_requests_controller.rb

@@ -140,7 +140,7 @@ class Projects::MergeRequestsController < Projects::ApplicationController
       format.json do
         begin
           render json: Gitlab::Conflict::FileCollection.new(@merge_request)
-        rescue Gitlab::Conflict::Parser::ParserError, Gitlab::Conflict::FileCollection::ConflictSideMissing => e
+        rescue Gitlab::Conflict::Parser::ParserError, Gitlab::Conflict::FileCollection::ConflictSideMissing
           render json: {
             message: 'Unable to resolve conflicts in the web interface for this merge request',
             type: 'error'