MB-15125: verbose logging for GsiClient.
MB-15125: verbose logging for GsiClient.

messages should look like, provided log level is set to `verbose`

Change-Id: I6b94789705880ee352751527135c38a1209f06cb
2015-07-31T18:02:59.203Z+05:30 [Verbose] CountRange elapsed(4.93257ms) err(<nil>)
2015-07-31T18:06:58.34Z+05:30 [Verbose] Lookup elapsed(5.023584ms) err(<nil>)
2015-07-31T18:07:15.341Z+05:30 [Verbose] Range elapsed(4.887184ms) err(<nil>)
2015-07-31T18:07:40.534Z+05:30 [Verbose] ScanAll elapsed(4.966072ms) err(<nil>)

jchris/indexing,jchris/indexing,jchris/indexing,jchris/indexing