[reSIProcate] More problems with `assert'

[Daniel Pocock <daniel@xxxxxxxxxxxxxxxxxxxxx>]

I occasionally see this piece of code causing trouble, assert at 
approximately line 1166 of DialogUsageManager.cxx (see code below).

Is it satisfactory to change the `assert' to something less 
catastrophic, like this for example:

#include <typeinfo>
...
if(dynamic_cast<SipMessage*>(msg.get()) == 0)
{
  ErrorLog(<< "discarding message of type " << 
typeid(*(msg.get())).name() <<", transaction gone away perhaps?");
  msg.release();
  return;
}

// From DialogUsageManager.cxx:

  if (tid != Data::Empty && !mIncomingFeatureList.empty())
  {
     FeatureChainMap::iterator it;
     //efficiently find or create FeatureChain, should prob. be a 
utility template
     {
        FeatureChainMap::iterator lb = 
mIncomingFeatureChainMap.lower_bound(tid);
        if (lb != mIncomingFeatureChainMap.end() && 
!(mIncomingFeatureChainMap.key_comp()(tid, lb->first)))
        {
           it = lb;
        }
        else
        {
           assert(dynamic_cast<SipMessage*>(msg.get()));
           it = mIncomingFeatureChainMap.insert(lb, 
FeatureChainMap::value_type(tid, new DumFeatureChain(*this, 
mIncomingFeatureList, *mIncomingTarget)));
        }
     }

     DumFeatureChain::ProcessingResult res = 
it->second->process(msg.get());