MFC r267812 (hrs): Fix ifname normalization. ifconfig_IF_alias{es,N} did not
work if ifname has any of [.-/+].
While here, also perform the following to reduce diff size between major
branches for etc/network.subr:
MFC r266475 (rea): Fix warning messages after r252015
$alias used to hold alias number, but now it carries full variable name,
so messages were tuned to account for that.
Other fixes:
- eliminate unneeded double spaces;
- tell user where inet/inet6 keywords are expected to be.
Reviewed by: hrs
Spotted by: jhay
PR: conf/191961
git-svn-id: svn://svn.freebsd.org/base/stable/10@269035
ccf9f872-aa2e-dd11-9fc8-
001c23d0bc1f