t/lib-httpd: pass GIT_TEST_SIDEBAND_ALL through Apache
07c3c2aa16 ("tests: define GIT_TEST_SIDEBAND_ALL", 2019-01-16) added
GIT_TEST_SIDEBAND_ALL to the apache.conf PassEnv list. Avoid warnings
from Apache when the variable is unset, as we do for GIT_VALGRIND* and
GIT_TRACE, from
f628825481 ("t/lib-httpd: handle running under
--valgrind", 2012-07-24) and
89c57ab3f0 ("t: pass GIT_TRACE through
Apache", 2015-03-13), respectively.
Signed-off-by: Todd Zullinger <tmz@pobox.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>