This change the write to accept an options hash to make
it compatible with ActiveSupport::Cache::Store#write method.
The options hash are not passed to the underlying cache
implementation because RequestStore#write accepts only
a key, and value params.
Makes it easier and safer to use RequestStore because you don't need to
check `RequestStore.active?` before using it. You just have to use
`Gitlab::SafeRequestStore` instead.
