MFstable/10 r299638:

MFstable/10 r299638:

MFC r298462:

Return `ret` in op_ifentry(..) to mute a -Wunused-but-set-variable warning

This will also now detect error conditions with
value->var.subs[sub - 1] == LEAF_ifPhysAddress where `string_get(..)`
could fail if iifp->physaddr and/or iifp->physaddrlen were deemed
invalid.

CID: 1006551

git-svn-id: svn://svn.freebsd.org/base/stable/9@299639 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f