Bug 1734609 - Make sure to not reuse a connection that has a mSpdySession, r=necko-reviewers,valentin

Differential Revision: https://phabricator.services.mozilla.com/D131617

netwerk/protocol/http/nsHttpConnection.cpp

@@ -238,6 +238,7 @@ void nsHttpConnection::Start0RTTSpdy(SpdyVersion spdyVersion) {
 
   mDid0RTTSpdy = true;
   mUsingSpdyVersion = spdyVersion;
+  mEverUsedSpdy = true;
   mSpdySession =
       ASpdySession::NewSpdySession(spdyVersion, mSocketTransport, true);