extensions: changed to call extsetup() from extensions.loadall()
previously uisetup() was invoked by extensions.loadall(), but
extsetup() was by _dispatch().
there's no need to split them because we have nothing to do
between uisetup() and extsetup().
this fixes
issue1824 indirectly.
adding a
marked working directory as branch b
adding b
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
fast-forward
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
bogus fast-forward should fail
abort: can't merge with ancestor
done