Bail out if you can't find memcached/vbucket.h
Bail out if you can't find memcached/vbucket.h

Change-Id: Ibb53626a36fa185dacb284100bd8ac9150fde3cd
Reviewed-on: http://review.couchbase.org/12190
Tested-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Reviewed-by: Matt Ingenthron <1fa2ef4755a9226cb9a0a4840bd89b158ac71391@couchbase.com>

signmotion/libcouchbase,signmotion/libcouchbase,mnunberg/libcouchbase,signmotion/libcouchbase,avsej/libcouchbase,kojiromike/libcouchbase,avsej/libcouchbase,PureSwift/libcouchbase,kojiromike/libcouchbase,mody/libcouchbase,avsej/libcouchbase,uvenum/libcouchbase,mnunberg/libcouchbase,uvenum/libcouchbase,senthilkumaranb/libcouchbase,avsej/libcouchbase,couchbase/libcouchbase,mody/libcouchbase,couchbase/libcouchbase,mody/libcouchbase,kojiromike/libcouchbase,senthilkumaranb/libcouchbase,maxim-ky/libcouchbase,senthilkumaranb/libcouchbase,uvenum/libcouchbase,senthilkumaranb/libcouchbase,signmotion/libcouchbase,PureSwift/libcouchbase,couchbase/libcouchbase,PureSwift/libcouchbase,trondn/libcouchbase,couchbase/libcouchbase,mnunberg/libcouchbase,trondn/libcouchbase,mody/libcouchbase,maxim-ky/libcouchbase,uvenum/libcouchbase,maxim-ky/libcouchbase,avsej/libcouchbase,trondn/libcouchbase,kojiromike/libcouchbase,uvenum/libcouchbase,mnunberg/libcouchbase,maxim-ky/libcouchbase,couchbase/libcouchbase,trondn/libcouchbase,mnunberg/libcouchbase,PureSwift/libcouchbase,couchbase/libcouchbase,avsej/libcouchbase,couchbase/libcouchbase,trondn/libcouchbase,avsej/libcouchbase