make target_wait_state() usable from other places, made LOG_USER() output...

make target_wait_state() usable from other places, made LOG_USER() output LOG_DEBUG() output. Avoids flooding logs in certain cases and OpenOCD will output error message if the halt fails.

git-svn-id: svn://svn.berlios.de/openocd/trunk@944 b42882b7-edfa-0310-969c-e2dbd0fdcd60