Fix the service-level rc_verbose setting

This commit fixes the rc_verbose setting so that it is honored if it is
set for an individual service.

Thanks to whissi@whissi.de for the original patch; this one is slightly
modified to be more posix.

X-Gentoo-Bug: 489358
X-Gentoo-Bug: https://bugs.gentoo.org/show_bug.cgi?id=489358