Instead of checking defaultMode for every channel that has no mode
configured, test it only once outside of channel loop.  This fixes a bug
that in case all possible channels are fore example set to insecure, but
defaultMode is set to secure, we wouldn't auto-generate TLS port.  This
results in failure while starting a guest.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1143832Signed-off-by: NPavel Hrdina <phrdina@redhat.com>