index redraw broken when sorting changes

[pdmef]

Redraw is broken in the index if the sorting method changes using <enter-command>, e.g. 'set sort=threads' when sort is 'date', or ':toggle strict_threads'.

The problem is that if the new index has more entries than with the old sort, mutt won't show all messages but only as many as there were in the old menu (though correctly sorted).

I think the bug is that menu->max with the entry count is computed before doing the resort, not after. The attached patch works for me.

[pdmef]

index redraw fix

[pdmef]

(In [7783502a04c7]) Calculate menu->max after a possible resort in index (maybe changing number of messages). Closes #3088.