Added checks to a couple scripts.

Add several checks to the scripts ensure sufficient permissions and to
carryout only the actions needed. Added a few checks to make sure
commands executed successfully. More such checks need to be added
in the future.

Changes:
 - scripts/AddBackupUser.sh
	2014/6/7	Added conditionals to carry out actions only if
		needed. Added root permision check.

 - scripts/SetupBackupServer
	2014/6/7	Added conditionals to carry out actions only if
		needed. Added root permision check.