Move genconfig/gencode to ../cmake/memcached

be moved back when ep-engine is being built by CMake

Change-Id: If7aaca45ec63e0b2aa9cc332873865943758d745
Reviewed-on: http://review.couchbase.org/29577
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Michael Wiederhold <mike@couchbase.com>