Remove 'LCB_CONNSTART_*' constants

These are pretty much specified by all systems which use a connection.

Change-Id: Idb6a8da73c7967e5a90f9f827721b75da7d2d9fd
Reviewed-on: http://review.couchbase.org/33602
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Brett Lawson <brett19@gmail.com>