Check service function types are present

Check service function types are present before attempting to create any
RSP making use of them. Otherwise RSP creation will fail if attempted
before the service function types exist. Service funtion types are
created by SFC as soon as the first SF of that type is added.

Change-Id: Iaa5d0bc966d0bb190e64ef8084b2243078d10fc6
Signed-off-by: Jaime Caamaño Ruiz <jcaamano@suse.com>