MB-6620: made capi_crud see correct item's rev
MB-6620: made capi_crud see correct item's rev

Previous implementation was obviously a stub. In order to return back
document with right rev, we need to send get_meta and handle possible
cas mismatch.

Change-Id: I34b3dff3d0eb13d09d74b09ccba551b8a23b5234
Reviewed-on: http://review.couchbase.org/21496
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Aliaksey Artamonau <3c875bcfb3adf2a65b2ae7686ca921e6c9433147@gmail.com>

ceejatec/ns_server,ceejatec/ns_server,vzasade/ns_server,membase/ns_server,ceejatec/ns_server,ceejatec/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,ceejatec/ns_server,mschoch/ns_server,nimishzynga/ns_server,mschoch/ns_server,membase/ns_server,daverigby/ns_server,membase/ns_server,t3rm1n4l/ns_server,mschoch/ns_server,pavel-blagodov/ns_server,pavel-blagodov/ns_server,ceejatec/ns_server,vzasade/ns_server,daverigby/ns_server,daverigby/ns_server,daverigby/ns_server,mschoch/ns_server,mschoch/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,membase/ns_server,membase/ns_server,pavel-blagodov/ns_server,mschoch/ns_server,nimishzynga/ns_server,nimishzynga/ns_server,daverigby/ns_server,vzasade/ns_server,vzasade/ns_server,pavel-blagodov/ns_server,t3rm1n4l/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,membase/ns_server