porting: include compat-errno.h for errno's

disperse module fails to compile since
ENODATA is non-existent on FreeBSD/Darwin

Use errno conversion in compat-errno.h to avoid
build issues.

Change-Id: I8203b7195c198c77202bde9bbec1813a487f923a
BUG: 1111774
Signed-off-by: Harshavardhana <harsha@harshavardhana.net>
Reviewed-on: http://review.gluster.org/8320
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Humble Devassy Chirammal <humble.devassy@gmail.com>