[BagOStuff] Converted RedisBagOStuff to RedisConnectionPool.

Change-Id: I9c269b77e51d335702146d15ebbfd38167c4ed1d
Avoid pool fragmentation in RedisConnectionPool.

* Avoid fragmenting the client pools due to "poolSize" differences.
  Instead that config parameter does not affect the pool something uses,
  but the pool used will grow to fit the pool size of anything using it.

Change-Id: Ibc9db7cfc277824b1acde5e6fbf1db0ed296cb41