quiltimport: Skip non-existent patches

When quiltimport encounters a non-existent patch in the series file,
just skip to the next patch. This matches the behavior of quilt.
Signed-off-by: NDan Nicholson <dbn.lists@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git-quiltimport.sh

@@ -71,6 +71,10 @@ commit=$(git rev-parse HEAD)
 
 mkdir $tmp_dir || exit 2
 for patch_name in $(grep -v '^#' < "$QUILT_PATCHES/series" ); do
+	if ! [ -f "$QUILT_PATCHES/$patch_name" ] ; then
+		echo "$patch_name doesn't exist. Skipping."
+		continue
+	fi
 	echo $patch_name
 	git mailinfo "$tmp_msg" "$tmp_patch" \
 		<"$QUILT_PATCHES/$patch_name" >"$tmp_info" || exit 3