p2p: don't reset timeout timer for handshakes

The handshake timeout should just be an absolute timeout, we don't
care about partial messages received during the handshake.

(cherry picked from commit c7c43686878166cd0b93bed0cc712c8dd9845c89)

contrib/epee/include/net/levin_protocol_handler_async.h

@@ -263,6 +263,8 @@ public:
     }
     virtual void reset_timer()
     {
+      if (m_command == connection_context::handshake_command())
+        return;
       boost::system::error_code ignored_ec;
       if (!m_cancel_timer_called && m_timer.cancel(ignored_ec) > 0)
       {