Added missing columns to flow table db and tests

Changed external-id column insert from 7.4.0 to 7.5.0
Changed prefixes insert from 7.3.0 to 7.4.0

Change-Id: Ic49aa37c756fb59c931a3d4f39e874b41e9b148e
Signed-off-by: Brent Salisbury <brent.salisbury@gmail.com>
Signed-off-by: Dave Tucker <djt@redhat.com>
Signed-off-by: Brent Salisbury <brent.salisbury@gmail.com>
Signed-off-by: Madhu Venugopal <mavenugo@gmail.com>
Merge "Added missing columns to flow table db and tests" into topic/schema