Remove "unused" stat command "connections"

The information don't make much sense for the average user

Change-Id: I9176640af30a2ae2d1931d0790ffea0e1a5b3c6c
Reviewed-on: http://review.couchbase.org/38737
Tested-by: Trond Norbye <trond.norbye@gmail.com>
Reviewed-by: Dave Rigby <daver@couchbase.com>