Merge branch 'bug26158_031' into maint-0.3.1

changes/bug26158

+   o Minor bugfixes (relay):
+     - Relays now correctly block attempts to re-extend to the previous
+       relay by Ed25519 identity. Previously they would warn in this case,
+       but not actually reject the attempt. Fixes bug 26158; bugfix on
+       0.3.0.1-alpha.

src/or/circuitbuild.c

@@ -1267,6 +1267,7 @@ circuit_extend(cell_t *cell, circuit_t *circ)
     log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
            "Client asked me to extend back to the previous hop "
            "(by Ed25519 ID).");
+    return -1;
   }
 
   n_chan = channel_get_for_extend((const char*)ec.node_id,