ASGARD-1119 - Fix AMI launch NPE

Deleting some old logic that compares architectures between AMIs and
instance types. This complexity is no longer useful, since all Amazon
instance types now support x86_64/64-bit architectures, including
m1.small.
Merge pull request #277 from joesondow/ASGARD-1119-AMI-launch-instance-NullPointerException

ASGARD-1119 - Fix AMI launch NPE
Remove unused imports
Merge pull request #278 from joesondow/ASGARD-1119-AMI-launch-instance-NullPointerException

Remove unused imports