prefer https urls

doc/spec/README

@@ -1,10 +1,11 @@
 The Tor specifications and proposals have moved to a new repository.
 
-To browse the specifications, go to 
+To browse the specifications, go to
     https://gitweb.torproject.org/torspec.git/tree
 
 To check out the specification repository, run
     git clone git://git.torproject.org/torspec.git
 
 For other information on the repository, see
-    http://gitweb.torproject.org/torspec.git
+    https://gitweb.torproject.org/torspec.git
+