kdepimlibs-4.7.3 imap4 regression fix

Attention Gentoo users: If you're running kmail-4.4.11.1 and kde-4.7.3, and if you have been hit by bug 382411 (problems with local filters, cannot upload unread message on imap; see also here and here), please keyword kde-base/kdepimlibs-4.7.3-r1 and give it a try. (You may want to log out and log back in.) This upgrade seems to fix the problem... If I get some positive feedback, I'll fast-track it for stabilization. Cheers!