Factoring of jtag_examine_chain for maintainability:

- Factor end-of-chain verfication into new helper routine.
- Change 'unexpected' local variable name to 'triggered' and type to bool.


git-svn-id: svn://svn.berlios.de/openocd/trunk@2086 b42882b7-edfa-0310-969c-e2dbd0fdcd60