daemon: improve warning on missing SO_ACCEPTFILTER

daemon: improve warning on missing SO_ACCEPTFILTER

I noticed tests were failing on a freshly booted FreeBSD
instance due to the accf_http module not being loaded and
triggering autodie-generated error messages from setsockopt.
Instead, give a helpful warning message for users to use
kldload(8) to load the necessary filter.

We'll also relax tests to ignore the kldload warning and fix an
overzealous use of /.*/ while we're at by using /[^\n]/ instead
to avoid filtering out subsequent lines.