Improve error message for key not found on instance run - EUCA-8921

EUCA-8921
Improve error message for unsupported/invalid SSH keys - EUCA-8955

EUCA-8955
EC2 virtualization type now paravirtual, was paravirtualized - EUCA-8903

EUCA-8903
Merge remote-tracking branch 'origin/dev/sjones/EUCA-8903' into testing
Merge remote-tracking branch 'origin/dev/sjones/EUCA-8921' into testing