Not optimal query in DatabaseBackend::garbageCollection()

This path fixes the typo in query.

The second parameter for the method range() for a select query is the number of rows that the query should return. The query also does a fetchField() which only needs a single row from the query. Therefor the code change is the correct one.
I do not see how we can test change. Without the change is the method garbageCollection() not failing, it is just a bit slower.
For me it is RTBC.

Good find. Committed/pushed to 10.1.x, cherry-picked to 10.0.x and 9.5.x, thanks!

Automatically closed - issue fixed for 2 weeks with no activity.