libblkid: add debug messages for "idmag" stuff and btrfs

Signed-off-by: Karel Zak <kzak@redhat.com>
add missing rpmatch.h everywhere it needs to be

Signed-off-by: William Pitcock <nenolod@dereferenced.org>
Signed-off-by: Karel Zak <kzak@redhat.com>