Move more tests over to the MockClient

And add a basic test of some of the MockRequests (just to
verify that they are detected and executed). Fixup a bug
in the HTTP mock request that wouldn't properly fixup
commands with space in them.

Change-Id: Ib10fb283051daf4e9794b9c7d2a86d482266944a
Reviewed-on: http://review.couchbase.org/27909
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>
Tested-by: Trond Norbye <trond.norbye@gmail.com>