Fix for issue #910: Bad packet received by server when hearbeat is en…

…abled (#911)

* Fix for issue #910: Bad packet received by server when hearbeat is enabled

* Address re-keying case too

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Co-authored-by: Jeroen van Erp <jeroen@hierynomus.com>

src/main/java/net/schmizz/sshj/transport/TransportImpl.java

@@ -420,9 +420,9 @@ public long write(SSHPacket payload)
         try {
 
             if (kexer.isKexOngoing()) {
-                // Only transport layer packets (1 to 49) allowed except SERVICE_REQUEST
+                // Only transport layer packets (1 to 49) allowed except SERVICE_REQUEST and IGNORE
                 final Message m = Message.fromByte(payload.array()[payload.rpos()]);
-                if (!m.in(1, 49) || m == Message.SERVICE_REQUEST) {
+                if (!m.in(1, 49) || m == Message.SERVICE_REQUEST || m == Message.IGNORE) {
                     assert m != Message.KEXINIT;
                     kexer.waitForDone();
                 }