[horde] upgrade imp to 4.2

[Joe Fisher]

> I'm getting the following errors:
> Notice: Undefined index: cachejs in
> /usr/local/cpanel/base/horde/imp/lib/IMP.php on line 1872
> 
> Notice: Undefined index: cachecss in
> /usr/local/cpanel/base/horde/imp/lib/IMP.php on line 2021
> 
> And in compose:
> Same thing
> 
> What should I do?
> 
> Joe

I was wondering if someone can point out what I've missed in my attempt
to update to 4.2 from 4.1?