* Fix tags in ec2_instance_facts
The method boto3_tag_list_to_ansible_dict in module_utils/ec2.py changed
and does no longer check whether the returned result of boto3 uses
"key" or "Key" as the tag key identifier.
This fixes ec2_instance_facts to make this check in its own, since boto3
may return "key" instead of "Key"
* Since the indices for the tags are already formatted to lowercase
by the snaking, we can assume, that the index for the tags are already
formatted