Retry for duplicate AMI name fails during register_ami

[kvick]

Ran into a team that had a bake failed due to a duplicate AMI name during registration. We normally handle this, but with the boto2 to boto3 change, it might be due to the change in variable from name to Name

`
2017-06-15 19:16:30 [DEBUG] [aminator.plugins.cloud.ec2(391):_register_image] Boto3 registration request data [{'VirtualizationType': 'paravirtual', 'Name': 'foo-service-283.0-h7253.137aa0b-x86_64-20170615174214-xenial-pv-ebs', 'EnaSupport': False, 'BlockDeviceMappings': [{'DeviceName': '/dev/sda1', 'Ebs': {'DeleteOnTermination': True, 'SnapshotId': u'snap-somesnapshotid', 'VolumeSize': 10, 'VolumeType': 'standard'}}, {'DeviceName': '/dev/sdb', 'VirtualName': 'ephemeral0'}, {'DeviceName': '/dev/sdc', 'VirtualName': 'ephemeral1'}, {'DeviceName': '/dev/sdd', 'VirtualName': 'ephemeral2'}, {'DeviceName': '/dev/sde', 'VirtualName': 'ephemeral3'}], 'Architecture': 'x86_64', 'KernelId': u'aki-919dcaf8', 'RootDeviceName': '/dev/sda1', 'Description': 'name=foo-service, arch=x86_64, ancestor_name=foobase-x86_64-201706081736-ebs, ancestor_id=ami-someid, ancestor_version=some-base-5.16.0-h17.088774d'}]

2017-06-15 19:16:31 [DEBUG] [aminator.plugins.volume.linux(113):exit] Exception encountered in linux volume plugin context manager
Traceback (most recent call last):
File "/apps/python/local/lib/python2.7/site-packages/aminator/environment.py", line 66, in provision
success = finalizer.finalize()
File "/apps/python/local/lib/python2.7/site-packages/aminator/plugins/finalizer/tagging_ebs.py", line 85, in finalize
if not self._register_image():
File "/apps/python/local/lib/python2.7/site-packages/aminator/plugins/finalizer/tagging_ebs.py", line 72, in _register_image
if not self._cloud.register_image(block_device_map, root_device):
File "/apps/python/local/lib/python2.7/site-packages/aminator/plugins/cloud/ec2.py", line 463, in register_image
if not self._register_image(ami_metadata):
File "", line 2, in _register_image
File "/apps/python/local/lib/python2.7/site-packages/aminator/plugins/cloud/ec2.py", line 71, in _retry
log.debug('Duplicate AMI Name {0}, retrying'.format(kwargs['name']))
KeyError: 'name'
`