largefiles: use 'default' instead of 'default-push' when pulling (issue3584)
This only applies to downloading largefiles, and only when no source for the
pull is explicitly provided. The repository itself was properly being pulled
via 'default' previously.
Using --all-largefiles is not necessary on a bare pull to test this (this
existing test is merely a convenience), but it is required to test pulling on
the rebase path.
Note that the errors generated in the --rebase case are because the repo
specified doesn't have the largefiles in its cache (though they are in the user
cache), so the errors are misleading. Specifying --all-largefiles when cloning
to 'b' fixes this, but instead of errors, it reports caching only 5 largefiles
instead of the 9 that come up missing. Likely this is because the largefile
download procedure tries to download missing files for each rev, and some of the
files have standins in more than one rev that gets pulled.