rowcache: delete socket file before and after memcache
rowcache: fix race condition between Open, Close & Put
planbuilder: compute table name first.

Setting the table name in the plan upfront gives us
more info about the query, which is useful for
blacklisting, etc.
Merge branch 'master' into vtocc
tabletserver: refactor transaction pool
Refactored keyrange.py and added documentation.
small linter improvements.
Fix for test breakage.
Merge branch 'master' of github.com:youtube/vitess
Fix issues in vtgate test.
Use shard '80-' to expose problems better.
Merge branch 'liguo'

Conflicts:
	test/vtgatev2_test.py
Fix vtrouting.py
Disable the problematic testcase in vtgate test