GIT-VERSION-GEN: support non-standard $GIT_DIR path
GIT-VERSION-GEN: support non-standard $GIT_DIR path

make and make test both work when $GIT_DIR isn't .git, but make dist
included a bogus GIT-VERSION-FILE.

Signed-off-by: Dennis Kaarsemaker <7965a665163253a12f43312bf69d07012a113a2a@kaarsemaker.net>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git