Make the creds file optional and configurable.  Provide
ec2_consistent_snapshot::creds for making more credentials files.
Add defined ec2_consistent_snapshot::creds type for more felxible creds
file creation.  Also don't createw the global file in profile.d if
$access_key and $secret have not been defined when calling
ec2_consistent_snapshot.
Anchor ec2_consistent_snapshot::creds into ec2_consistent_snapshot
remove setting $file_ensure since we no longer need it.
Merge pull request #3 from hubspotdevops/configurable_credentials_hsmaster

Configurable credentials hsmaster