vtctld: sort children in the ZK explorer.
Merge pull request #15 from youtube/vtctld-sort-children

vtctld: sort children in the ZK explorer.
Merge pull request #17 from youtube/reparent-fix

Fixing lock release in reparenting on error.
rowcache: bug fix on closing of CachePool
Merge pull request #18 from youtube/sougou-work

rowcache: bug fix on closing of CachePool
Checking the tablet type is valid.