syslogd: Fix function return test

Looks like during the capsicum setup the return value for cap_syslogd
is checked twice rather than checking the return value of cap_net
after initializing the casper service.

Signed-off-by: Nathan Huff <nhuff@acm.org>
Fixes: 897240c7d666 ("syslogd: Enter capability mode")
Pull-request: https://github.com/freebsd/freebsd-src/pull/1796