Revert "Merge branch 'lock_fix' into 'master'"

This reverts commit d836a359.

db/migrate/20160827011312_ensure_lock_version_has_no_default.rb

-class EnsureLockVersionHasNoDefault < ActiveRecord::Migration
-  include Gitlab::Database::MigrationHelpers
-
-  DOWNTIME = false
-
-  def up
-    change_column_default :issues, :lock_version, nil
-    change_column_default :merge_requests, :lock_version, nil
-
-    execute('UPDATE issues SET lock_version = 1 WHERE lock_version = 0')
-    execute('UPDATE merge_requests SET lock_version = 1 WHERE lock_version = 0')
-  end
-
-  def down
-  end
-end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20160827011312) do
+ActiveRecord::Schema.define(version: 20160819221833) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"