xvfb issue for lsb-vsw4

All

A bunch of problem reports came in overnight related to 
lsb-vsw4. The test strategy (employed by the lsb version of
vsw4) uses the X Virtual Frame Buffer. 

Some implementations do not have an xvfb with "backing store" enabled.
This can cause a large number of tests to be resolved .

See problems 85 thru 87
http://www.opengroup.org:8000/lsb/publicpr/PRSummary

Also
http://bugs.linuxbase.org/show_bug.cgi?id=1061

The choice is to 

(1) require that the implementation provide an xvfb which is configured
with backing store to run the tests and reject the problem report
on those grounds. There is nothing that states that the xvfb has
to be the one installed on the system, the one used for testing
could be a different instance,historically xvfb has worked ok
out of the box.

or
(2) grant a TSD waiver for these tests, which implies that these
tests would be rewritten not to require that the display has backing store.

Since  this is test setup required to run these tests, and a conscious
choice by the test developers, I would lean towards 1.

regards
Andrew