t9600-cvsimport.sh: set HOME before checking for cvsps availability

t9600-cvsimport.sh: set HOME before checking for cvsps availability

This actually sounds like a bug in cvsps, which requires an existing
home directory when asked for the usage through -h

 $ HOME=/nonexistent cvsps -h
 Cannot create the cvsps directory '.cvsps': No such file or directory

This made t9600 think that cvsps is not available if HOME did not exist,
causing the tests to be skipped

 $ HOME=/nonexistent sh t9600-cvsimport.sh
 * skipping cvsimport tests, cvsps not found
 * passed all 0 test(s)

Now t9600 sets HOME to the current working directory before checking for
the availability of the cvsps program.

This issue has been discovered by Marco Rodrigues, and fixed by Frank
Lichtenheld through
 http://bugs.debian.org/471969

Signed-off-by: Gerrit Pape <pape@smarden.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>