The current code runs "perl gitweb.cgi" to test gitweb. This
will use whatever version of perl happens to be first in the
PATH. We are better off using the specific perl that the
user specified via PERL_PATH, which matches what gets put on
the #!-line of the built gitweb.cgi.
Signed-off-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>