submodule.c: use GIT_DIR_ENVIRONMENT consistently
commitc5f3cba1266dc4feb4101f85e5596912fdb10d5b
authorStefan Beller <sbeller@google.com>
Tue, 3 Jan 2017 18:30:47 +0000 (3 10:30 -0800)
committerJunio C Hamano <gitster@pobox.com>
Sat, 7 Jan 2017 21:10:02 +0000 (7 13:10 -0800)
tree0a7dea1586a8552247a21aa05a8c724f9c6501d1
parente05806da9ec4aff8adfed142ab2a2b3b02e33c8c
submodule.c: use GIT_DIR_ENVIRONMENT consistently

In C code we have the luxury of having constants for all the important
things that are hard coded. This is the only place in C that hard codes
the git directory environment variable, so fix it.

Signed-off-by: Stefan Beller <sbeller@google.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
submodule.c