largefiles: support revsets for outgoing --large
Previous to this, outgoing with a revset succeeded unless --large was also
specified.
Test issue2761
$ hg init
$ touch to-be-deleted
$ hg add
adding to-be-deleted
$ hg ci -m first
$ echo a > to-be-deleted
$ hg ci -m second
$ rm to-be-deleted
$ hg diff -r 0
Same issue, different code path
$ hg up -C
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
$ touch doesnt-exist-in-1
$ hg add
adding doesnt-exist-in-1
$ hg ci -m third
$ rm doesnt-exist-in-1
$ hg diff -r 1