f947413 (Use GIT_REFLOG_ACTION environment variable instead.,
2006-12-28) established git-pull's method for setting the reflog
message, which is to set the environment variable GIT_REFLOG_ACTION to
the evaluation of "pull${1+ $*}" if it has not already been set.
Re-implement this behavior.
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>