Fix possible nil pointer deref in interface check

This change address a potential nil pointer dereference when
building a list of interface names that might be used for
connection listening.

Issue-ID: RIC-307

Signed-off-by: E. Scott Daniels <daniels@research.att.com>
Change-Id: I3b63bebe31afc61073bd4d4093f1fb42d018963e
4 files changed