uri: really count dots in verify_uri_segment()

This buggy implementation failed to allow "..." sequences, because the
dot count was always zero.  The usefulness of allowing "..." (or more
dots) is debatable, but since it's a valid file name, we allow it.

src/uri.c

@@ -52,8 +52,11 @@ verify_uri_segment(const char *p)
 	const char *q;
 
 	unsigned dots = 0;
-	while (*p == '.')
+	while (*p == '.') {
 		++p;
+		++dots;
+	}
+
 	if (dots <= 2 && (*p == 0 || *p == '/'))
 		return NULL;