Making Nick Alexander owner of the Fennec build sub-module

[Gregory Szorc]

There is currently a sub-module of the Build Config module governing the
Fennec build system. The peers are all the Build Config peers plus Nick
Alexander. I am the current owner.

The sub-module was created to allow Fennec's build system to have some
autonomy from the overall build system and to help cultivate peers who
wanted to maintain Fennec's build system without the burden of becoming a
full build module peer.

In the course of reviewing a Fennec build system patch earlier today, I
looked at the peers list in preparation for possibly suggesting Nick
Alexander appoint some more peers to do these reviews and to my surprise I
- not Nick - was listed as the owner for the sub-module!

Nick Alexander has been spearheading improvements to Fennec's build system
for ages. He's effectively functioning as a module owner. I'd like to
formally propose that ownership of this sub-module be transferred from me
to Nick so he has more autonomy and authority to improve the Fennec build
system.

If I hear no objections by December 23, I'll consider silence as consent.

(I'm not sure if I need to follow this ownership change procedure for a
sub-module. If not, I apologize for the noise.)