t9501: Re-fix max load test

t9501: Re-fix max load test

Revert the previous attempt to skip this test on platforms where we
currently cannot determine the system load.  We want to make sure that
the max-load-limit codepath produces results cleanly, when gitweb is
updated and becomes capable of reading the load average by some other
method.

The code to check for load returns 0 if it doesn't know how to find
load.  It also checks to see if the current load is higher than the
max load.  So to force the script to quit early by setting the maxload
variable negative which should work for systems where we can detect
load (which should be a positive number) and systems where we can't
(where detected load is 0)

Signed-off-by: Brian Gernhardt <brian@gernhardtsoftware.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>