git-remote-mediawiki: refactor loop over revision ids

git-remote-mediawiki: refactor loop over revision ids

Without changing the behavior, we turn the foreach loop on an array of
revisions into a loop on an array of integer. It will be easier to
implement other strategies as they will only need to produce an array of
integer instead of a more complex data-structure.

Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>