Description of problem:

spacecmd activationkey_import will fail if the exported key did not have any channels set.

Version-Release number of selected component (if applicable):
Any

How reproducible:
spacecmd activationkey_export on a key with no base channel set.
try to import the same key on another server

Steps to Reproduce:
1. spacecmd activationkey_list -q | xargs -n 1 spacecmd  activationkey_export
2. change to another server
3. ls *.json | xargs -n 1 spacecmd activationkey_import
  
Actual results:
ERROR: redstone.xmlrpc.XmlRpcFault: Invalid channel


Expected results:
Successful import

Additional info:
There is also no way to remove base channels via the api (that I can find)

Thanks,
Trent