Hey Sk!d,
I think this is related to our source switch for httplib2 (from a github clone to our own gerrit repo).
I can think of two things to try;
git submodule sync should do that for you (why doesn't update --init also do that for you? Silly git)
2) the less subtle way: remove the submodule entries from .git/config, remove the directories under .git/modules and under externals/httplib2 and scripts/i18n.
Sorry for the inconvenience - but at least we're not going to switch repositories again ;-)
Merlijn