re[2]: snapshot regression test try 2

[Greg Freemyer <freemyer@xxxxxxxxxxxxxxxxx>]

  >>  > tmp=/tmp/$$

 >>  very predictable, use tmp=`mktemp -d` || exit 1

Someone with SGI,  

Ethan has recommended the above change to my script.  It is easy enough to do.  
As a matter of fact I have already done it.

Every other script in xfstests uses the tmp=/tmp/$$ as a prefix for temp files.

Ethan's recommendation is to use a unique directory and place temporary files 
in the directory.

I can see where Ethan's suggestion is better, but for consistency sake it may 
be better to put it back the way it was.

Please advise.

Greg