Merge branch 'jk/test-httpd-config-nosystem' into maint

The tests that involve running httpd leaked the system-wide
configuration in /etc/gitconfig to the tested environment.

* jk/test-httpd-config-nosystem:
  t/lib-httpd: pass through GIT_CONFIG_NOSYSTEM env

Author: gitster

t/lib-httpd/apache.conf

@@ -74,6 +74,7 @@ PassEnv GIT_VALGRIND_OPTIONS
 PassEnv GNUPGHOME
 PassEnv ASAN_OPTIONS
 PassEnv GIT_TRACE
+PassEnv GIT_CONFIG_NOSYSTEM
 
 Alias /dumb/ www/
 Alias /auth/dumb/ www/auth/dumb/