install-webdoc: keep installed RelNotes-*.txt

Otherwise URLs in the wild that point at older release notes will become
dangling.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/install-webdoc.sh b/Documentation/install-webdoc.sh
index e5c1cbe..76d69a9 100755
--- a/Documentation/install-webdoc.sh
+++ b/Documentation/install-webdoc.sh
@@ -30,7 +30,7 @@
 do
 	h=`expr "$th" : "$strip_leading"'\(.*\)'`
 	case "$h" in
-	index.html) continue ;;
+	RelNotes-*.txt | index.html) continue ;;
 	esac
 	test -f "$h" && continue
 	echo >&2 "# rm -f $th"