- make sure the etag buffer is non empty if we compare it with if-non-match

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@1971 152afb58-edef-0310-8abb-c4023f1b3aa9

src/etag.c

@@ -5,7 +5,7 @@
 #include "etag.h"
 
 int etag_is_equal(buffer *etag, const char *matches) {
-	if (0 == strcmp(etag->ptr, matches)) return 1;
+	if (etag && !buffer_is_empty(etag) && 0 == strcmp(etag->ptr, matches)) return 1;
 	return 0;
 }