It's better to give platform code a chance to specify the allowed
protocols to use.

[mchehab@redhat.com: fix merge conflict with a patch that made
 half of this change]
Signed-off-by: NDu, Changbin <changbin.du@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>