Fix buffer_reset to make an empty string

git-svn-id: svn://svn.lighttpd.net/lighttpd/branches/lighttpd-1.4.x@2270 152afb58-edef-0310-8abb-c4023f1b3aa9

src/buffer.c

@@ -55,6 +55,8 @@ void buffer_reset(buffer *b) {
 		free(b->ptr);
 		b->ptr = NULL;
 		b->size = 0;
+	} else if (b->size) {
+		b->ptr[0] = '\0';
 	}
 
 	b->used = 0;