[LTP] Updates to INSTALL documentation and addition IDcheck.sh script added

[Robert W. <ro...@us...>]

I added a note in the INSTALL file that mentions the requirement to have
the nobody, bin, and daemon users/groups.  I also wrote a small script to
check for these, which is ran in the Makefile.  A message is displayed at
the end of testcase compilation, on the results of the check.  The users
and/or groups are not created, so it's still up to the user to do this.

- Robbie

Robert V. Williamson
Linux Test Project
IBM Linux Technology Center
Phone: (512) 838-9295   T/L: 638-9295
http://ltp.sourceforge.net