vty: make 'sh connect/transact' readable again

After recent changes to vlr_subscr_name() result became variable-length
which messes up old vty code. Fix this by moving it to the very end and
adjusting headers as necessary. While at it, make sure we don't print
headers if we have nothing else to show.

Change-Id: Id06b4277ff790d95457d0cc2f94ef6bf5366bb21
1 file changed