Revert "kvs.cache_gc() uses provided logger"
Revert "kvs.cache_gc() uses provided logger"

This reverts commit 36bc243fffb3c76bba75a51dd79dd6a1031c262c.

Conflicts:

	openquake/kvs/__init__.py

gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine