We have 5 options plus ("server") option which is added in the next
patch that conflict with specifying a SSH filename. We need to iterate
over all the options to check whether its key has an "server." prefix.

This iteration will help us adding the new option "server" easily.
Signed-off-by: NAshijeet Acharya <ashijeetacharya@gmail.com>
Reviewed-by: NMax Reitz <mreitz@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>