pkgdelta: exit 1 upon error

This has been 0 since 9fa18d9a4b, but it
doesn't makes sense because we are raising an error.

Signed-off-by: Florian Pritz <bluewind@xinu.at>
Signed-off-by: Dan McGee <dan@archlinux.org>

scripts/pkgdelta.sh.in

@@ -136,12 +136,12 @@ fi
 
 if [[ ! -f $1 ]]; then
 	error "$(gettext "File '%s' does not exist")" "$1"
-	exit 0
+	exit 1
 fi
 
 if [[ ! -f $2 ]]; then
 	error "$(gettext "File '%s' does not exist")" "$2"
-	exit 0
+	exit 1
 fi
 
 if ! type xdelta3 &>/dev/null; then