change to behaviour of the ec2facts process

[freibuis]

If you add this module to a control repo. the fact will fire on all machines even if the class is not declared. at this point tje resources have not already been deployed.. example awscli and creds
this module will break nodes that are

• on aws but do not have creds
• on aws already using default creds (default profile collision)
• not on aws (longer facter runs) (well sort of because of http lookup failure)

what this pull request hopes to achieve is to

• if using creds file do not use [default] profile instead use --profile=puppet_ec2tags and move the creds into that section of the config
• tell facter to use --profile=puppet_ec2tags if file /root/.aws/.ectags_use_credentials_file exists
• adds an ability to disable facter from being fired. ( via /root/.aws/.ec2tags_enabled file) meaning it will not run unless this class has been declared or the admin has declared they want it.

The downside to this is that facter will not get ec2_tags the first time around.
The upside is that it will deploy faster first time and no prfile cred collisons

[tedivm]

If you want a faster deploy time check out the branch in #21. It explicitly checks for permission and if it isn't granted does not bother retrying the query.