init: having keywords without value is not a global error.

init: having keywords without value is not a global error.

We may later add a new configuration variable in "init" section that takes
a boolean value.  Erroring out at the beginning of the config parser makes
life harder for later enhancement.

The existing configuration variable is parsed by git_config_pathname()
that checks and rejects init.templatedir that is unset without this extra
check.  Remove it.

Signed-off-by: Steven Drake <sdrake@xnet.co.nz>
Signed-off-by: Junio C Hamano <gitster@pobox.com>