camera: don't fail when selecting channel 0 without Selector missing
camera: don't fail when selecting channel 0 without Selector missing

There is no reason to return an error if a user try to select the only
stream channel available. May be we should check StreamChannelCount
though.

AravisProject/aravis,AravisProject/aravis,AravisProject/aravis,AravisProject/aravis,AravisProject/aravis