Use the migration name as a key in redis

lib/gitlab/database/rename_reserved_paths_migration/v1/rename_base.rb

@@ -144,7 +144,7 @@ module Gitlab
           end
 
           def redis_key_for_type(type)
-            "rename:#{migration.version}:#{type}"
+            "rename:#{migration.name}:#{type}"
           end
 
           def file_storage?

spec/lib/gitlab/database/rename_reserved_paths_migration/v1/rename_base_spec.rb

@@ -231,7 +231,7 @@ describe Gitlab::Database::RenameReservedPathsMigration::V1::RenameBase, :trunca
 
   describe '#track_rename', redis: true do
     it 'tracks a rename in redis' do
-      key = 'rename:20170316163845:namespace'
+      key = 'rename:FakeRenameReservedPathMigrationV1:namespace'
 
       subject.track_rename('namespace', 'path/to/namespace', 'path/to/renamed')
 

spec/support/fake_migration_classes.rb

@@ -4,4 +4,8 @@ class FakeRenameReservedPathMigrationV1 < ActiveRecord::Migration
   def version
     '20170316163845'
   end
+
+  def name
+    "FakeRenameReservedPathMigrationV1"
+  end
 end