SSH: Fix key re-exchange bug.

We used the encrypted client payload by mistake. The bug only manifests
itself from the second key exchange on, because during the first one,
no encryption is active, so the "encrypted" payload is the same as
the non-encrypted one.

src/libs/utils/ssh/sshoutgoingpacket.cpp

@@ -55,7 +55,7 @@ quint32 SshOutgoingPacket::macLength() const
     return m_encrypter.macLength();
 }
 
-void SshOutgoingPacket::generateKeyExchangeInitPacket()
+QByteArray SshOutgoingPacket::generateKeyExchangeInitPacket()
 {
     const QByteArray &supportedkeyExchangeMethods
         = encodeNameList(SshCapabilities::KeyExchangeMethods);
@@ -81,7 +81,9 @@ void SshOutgoingPacket::generateKeyExchangeInitPacket()
     m_data.append(supportedLanguages).append(supportedLanguages);
     appendBool(false); // No guessed packet.
     m_data.append(QByteArray(4, 0)); // Reserved.
+    QByteArray payload = m_data.mid(PayloadOffset);
     finalize();
+    return payload;
 }
 
 void SshOutgoingPacket::generateKeyDhInitPacket(const Botan::BigInt &e)