More packet metrics (#1982)

* found path negotation sends that weren't accounted for

* Fix histogram so it will actually compile

* Found more places for packet metrics

node/Membership.cpp

@@ -100,6 +100,7 @@ void Membership::pushCredentials(const RuntimeEnvironment *RR,void *tPtr,const i
 
 		outp.compress();
 		RR->sw->send(tPtr,outp,true);
+		Metrics::pkt_network_credentials_out++;
 	}
 
 	_lastPushedCredentials = now;