BUGFIX: FindResidue with a ost.mol.ResNum containing ins code

An ins code in the search ResNum caused a jump to the next residue.
The assertion that should've catched this is optimized away with -O3.
The new behaviour returns an invalid residue if the exact ResNum
(including ins code) is not present in these cases.

modules/mol/base/src/impl/chain_impl.cc

@@ -409,7 +409,9 @@ int ChainImpl::GetIndexForResNumInSequence(const ResNum& number) const
   if (pos<0 || pos>=static_cast<int>(residue_list_.size())) {
     return -1;
   }
-  assert(residue_list_[pos]->GetNumber()==number);
+
+  if(residue_list_[pos]->GetNumber()!=number) return -1;
+
   return pos;
 }