aufs: changed to apply local patches thand end with .patch instead of .diff file suffix

This mimics the standard behavior of OpenSDE for normal package builds,
where .patch files found in the $confdir are unconditionally applied,
whereas .diff files are commonly added to the patch file list based on
some conditions defined in the package conf.

filesystem/aufs/pkg_linux_post.conf

@@ -31,7 +31,7 @@ if [ ! -z "$pkg_aufs_source_file" ]; then
 	var_append patchfiles ' ' "$pkg_aufs_tempdir/aufs3-standalone/aufs3-standalone.patch"
 
 	# apply possible local patches we have in the aufs package dir
-	for x in $( ls -1 $base/package/*/aufs/*.diff 2>/dev/null ); do
+	for x in $( ls -1 $base/package/*/aufs/*.patch 2>/dev/null ); do
 		var_append patchfiles ' ' "$x"
 	done