Add error reporting for vbucket_config_parse_file().
Add error reporting for vbucket_config_parse_file().

Change-Id: I49a33bb0737fc3f4b5502caddd709dd076b94bfa
Reviewed-on: http://review.northscale.com:8080/266
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

zbase/libvbucket,membase/libvbucket,zbase/libvbucket,zbase/libvbucket,couchbase/libvbucket