Streamline Capture-IR validation code

Streamline Capture-IR validation code

 - Don't issue needless JTAG resets ... only do them after
   errors. Normal exit now leaves every TAP in BYPASS.

 - Fix an unlikely memory leak on one fault path.

 - Remove the oddball limitation that invalid capture LSBs
   trigger errors only for TAPs that support IDCODE.

Re the JTAG reset:  there are too many of them, and they can
(and do!) change system state.  So the needless ones should
get removed.  This one was especially pointless.

git-svn-id: svn://svn.berlios.de/openocd/trunk@2777 b42882b7-edfa-0310-969c-e2dbd0fdcd60