MB-8903: Make function names more uniform

Remove "request" from encode_open_connection_request

Change-Id: I7343c3ac66af523afcf4d4692aed5a0214eb4a5a
Reviewed-on: http://review.couchbase.org/30175
Reviewed-by: Filipe David Borba Manana <fdmanana@gmail.com>
Tested-by: Volker Mische <volker.mische@gmail.com>