ui-plain: fix resource leak: free before assigning NULL

Coverity-id: 13939
Signed-off-by: Christian Hesse <mail@eworm.de>

ui-plain.c

@@ -84,8 +84,10 @@ static void print_dir(const unsigned char *sha1, const char *base,
 		slash = strrchr(fullpath, '/');
 		if (slash)
 			*(slash + 1) = 0;
-		else
+		else {
+			free(fullpath);
 			fullpath = NULL;
+		}
 		html("<li>");
 		cgit_plain_link("../", NULL, NULL, ctx.qry.head, ctx.qry.sha1,
 				fullpath);