Fix support of iotype=Double32_t when using Cintex.

If iotype=Double32_t is used in a selection.xml, for Cintex to
properly pass the information to CINT, it (well Reflex actually)
needs to know about the Double32_t typedef.
Remove a couple of gotos
Remove one more goto
Correct the error handling in TInterpreter::Execute(...,TObjArray*)

The issues at http://root.cern.ch/phpBB3/viewtopic.php?f=3&t=16769
was actually about not handling correctly defaulted parameters
and not about the 'this pointer'.

In addition LastIndex for a TObjArray is not as reliable as for
TList to get the number of entries in the collection (i.e. it
was wrong to use it here).
  Remove bad fclose() calls introduced in e5b0b42b

  These fclose calls were added by mistake during a code cleanup during port to
  xrootd 3.3.x . The bug is fatal when authentication is enabled and affects all
  5.34 versions 5.34/06 to 5.34/09 .