General tidy ups and corrections.

2013-01-23  Jeremy Bennett <jeremy.bennett@embecosm.com>

	* arc-init.sh (save_res): Append errors to log, not overwrite.
	* dejagnu/baseboards/arc-linux-aa4.exp: Improve commenting, and
	general password field.
	* run-elf32-tests.sh: Add target_dir.
	* run-tests.sh: Tidy up error messages. Add better commenting
	* run-uclibc-tests.sh: Make target_dir generic, tidy up layout