Use the new codebase for autoinstalls, check for None

Don't try to blindly check the length of variables which may be
None, and don't use the old codebase to get kernel commandline
arguments when we can use the new codebase.

Change-Id: I198eb9438f10c748aa0323ef398cfa21dea9896f
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1120650
Signed-off-by: Ryan Barry <rbarry@redhat.com>