[reSIProcate] invite session handler end method

[Neal Sidhwaney]

Hi

I've started getting an assert inside

resip::ClientInviteSession::end()

since upgrading from resiprocate .4 to 1.0.  Our
InviteSessionHandler::onTerminated override calls this method, but
from looking at the code in

resip::ClientInviteSession::dispatchStart+0x7b5

It appears that there is a transition to Terminated before our handler
is called, so if our handler calls end(), it will assert because the
state will already be terminated.  Are we not supposed to do this?  In
one instance, this code path was triggered when the remote end did not
answer a call.

Thanks!

Neal