4552: Fix conflict between ensure_unique_name and signed manifests.
4552: Use faster database_cleaner strategy.
4552: Tidy up ensure_unique_name block.
4400: Silence git error messages during package install (we ignore them anyway)
4552: Set permit_unsigned_manifests=false needed for test.
Merge branch '4552-collection-unique-name' closes #4552

Conflicts:
	services/api/app/models/collection.rb