Allow multiple users to use ec2 inventory scripts

Move the ec2 cache files from a shared /tmp location to the
user's ansible tmp directory.
Fail EC2 inventory better with restricted EC2 users

If a user has full EC2 access but no RDS access, the user
should still be able to query the EC2 inventory, although
will not obtain any information about any RDS instances.
Update latest released version of ansible to 1.4.4 on docsite
Fixed splitting of role/user name when username has a '.' in it

This may still be an issue if users create roles with a '.' in the name though.
We will probably have to disallow that in the role naming convention.
Fixes #5196 return a unique list of hostnames for a single host pattern
Fixes #5227 Corrected doc example of with_first_found
Merge pull request #5153 from willthames/ec2_inventory_multiuser

Allow multiple users to use ec2 inventory scripts
Merge pull request #5236 from willthames/ec2_inv_rds_fail_safe

ec2 inventory: Fail EC2 inventory better with restricted EC2 users
Fixes #5238 Improve error messaging about unquoted variable references in playbooks