[imp] php 4.3 problem: session.bug_compat_42

[Ethan Tuttle]

> I fixed all of these in Turba in HEAD a while back, and I just merged
those
> changes to RELENG.  I fixed IMP also.

Thanks, your change to imp/login.php has done the trick for me.  I made
session.bug_compat_warn = On in php.ini and the warning has not re-appeared.

Thanks!

Ethan