Removed Rescan Buckets button from UI.
Fix log msg since cbgb now lazily loads buckets.
Removed logTapMutation cmd-line flag.

Not really used, and helpful to get it out of the way for a
forthcoming change where tap observers will prevent bucket quiescence.
Don't quiesce any observed (TAP'ed) buckets.

Workaround fix so that cbgb can meet sync-gateway's expectations.

See: https://github.com/couchbase/sync_gateway/issues/169

Currently, when a bucket is quiesced, any related TAP goroutines are
left pointing to the wrong livebucket instance.  A real fix would
address that issue, whereas this "fix" (in the name of faster
turnaround) just prevents quiescence for any TAP'ed or observed
buckets.