libalias: Style cleanup

libalias is a convolut of various coding styles modified by a series
of different editors enforcing interesting convetions on spacing and
comments.

This patch is a baseline to start with a perfomance rework of
libalias. Upcoming patches should be focus on the code, not on the
style. That's why most annoying style errors should be fixed
beforehand.

Reviewed by: hselasky
Discussed by: emaste
Differential Revision: https://reviews.freebsd.org/D30259

(cherry picked from commit effc8e57fbf03d7f1423c662caf2b63f0d1d21a9)

At some places the ASSERT was inserted before variable declarations are
finished. This is fixed now.

Reported by: kib
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D30282

(cherry picked from commit 2e6b07866f9e1520626a1523f6609cc411bdda1c)