Fix rubocop errors [ci skip]

app/models/project_services/mattermost_slash_commands_service.rb

@@ -24,13 +24,13 @@ class MattermostSlashCommandsService < ChatSlashCommandsService
       create(command(params))
 
     update(active: true, token: token) if token
-  rescue => Mattermost::Error => e
-    false, e.message
+  rescue Mattermost::Error => e
+    [false, e.message]
   end
 
   def list_teams(user)
     Mattermost::Team.new(user).all
-  rescue => Mattermost::Error => e
+  rescue Mattermost::Error
     []
   end
 

lib/mattermost/client.rb

@@ -34,7 +34,7 @@ module Mattermost
       end
 
       json_response
-    rescue JSON::JSONError => e
+    rescue JSON::JSONError
       raise ClientError('Cannot parse response')
     end
   end

spec/features/projects/services/mattermost_slash_command_spec.rb

@@ -41,7 +41,6 @@ feature 'Setup Mattermost slash commands', feature: true do
       end
     end
 
-
     describe 'mattermost service is not enabled' do
       before do
         allow(Gitlab.config.mattermost).to receive(:enabled).and_return(false)