Remove references to obsolete directory appliance/debian.

This directory has not existed for a long time.
(cherry picked from commit fc198a3b9a)

.x-sc_TAB_in_indentation

@@ -1,4 +1,3 @@
-^appliance/debian/modules/
 ^tests/data/
 ^COPYING(.LIB)?$
 ^\.gitmodules$

Makefile.am

@@ -253,7 +253,6 @@ all-local:
 	grep -v '^perl/examples/' | \
 	grep -v '/guestfs_protocol.c' | \
 	grep -v '/rc_protocol.c' | \
-	grep -v 'appliance/debian/root' | \
 	grep -v '^po-docs/' | \
 	grep -v '^images/' | \
 	LC_ALL=C sort | \