Resigning as the Necko module owner

Hi all,

I've been the necko module owner for many years now, but lately I have had
very little time to work on Mozilla-related things. Therefore, I decided
it's time to hand over the module ownership to Patrick McManus, who has
been doing excellent work in Necko.

I'm still going to do reviews and super-reviews and am available for
questions and help, but I feel that listing me as the owner is going to
give people the wrong impression at this point.

-christian