pull: remove redirection to git-pull.sh
At the beginning of the rewrite of git-pull.sh to C, we introduced a
redirection to git-pull.sh if the environment variable
_GIT_USE_BUILTIN_PULL was not defined in order to not break test scripts
that relied on a functional git-pull.
Now that all of git-pull's functionality has been re-implemented in
builtin/pull.c, remove this redirection, and retire the old git-pull.sh
into contrib/examples/.
Signed-off-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>