daemon: set supervise_enabled during argument processing

Now when supervsion mode has it's own variable there is really no
reason to set it separately from the rest of the variables. Move
initialization of supervise_enabled var to the argument processing
switch loop, where it belongs.

Reviewed by: kevans
Pull Request: https://github.com/freebsd/freebsd-src/pull/672

(cherry picked from commit f907027b49d93170ed2e92cf0d183cd643b1f70e)