[NaCl SDK AppEngine] Fix URLs to support loading from https.

It's unfortunately difficult to test whether this works; I pushed to a
different version on appspot, but https is not allowed there (the certs are
invalid). I've confirmed that http still works, however.

* Also, update .pexes to non-dev versions.
* Also, actually land the change to update docs -> dev.

BUG=none
R=sbc@chromium.org

Review URL: https://codereview.chromium.org/83793005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237102 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237102