Update rax to sync with rax_clb_nodes

Both modules dealing with rax resources should use the same arguments
and environmental variables. The author of rax_clb_nodes did some things
better so sync rax with that effort.
Added git disclaimer about dealing with ssh host checking

This disclaimer already exists in library/source_control/hg but not here.  It affects both and was discussed awhile back on: https://groups.google.com/forum/#!msg/ansible-project/q9G9xIdsRxo/XJhQzuS-qSoJ  However no PR was ever sent to fix the doc.
Add openshift inventory plugin

This plugin will list all your git repositories from a openshift
provider, and allow you to manage them using ansible.

The inventory either use a environement variable or reuse the
existing rhc configuration file if it exist.
Introduced ansible-rsync to core.
Fixed identity key logic.
Straighten out local-remote-delegate logic in rsync action module. Force set delegate to local if one is not defined.
Implemented setup method in rsync action module.
Merge branch 'ansible-rsync-take2' of git://github.com/tima/ansible into rsynctake2
Style/docs cleanup, and also improve an error message.
Update changelog
fix inventory.basedir is not absolute path when hostfile is startswith "./"
Brings postgresql_db examples in line with documentation.

As of now, the documentation lists a parameter as "name",
whereas the examples use a parameter called "db". This brings
them in line.
update docsite about new variable inventory_file
Fix some typos discovered during casual reading
Merge pull request #3816 from DanLovesProofs/fix-docs

Brings postgresql_db examples in line with documentation.
Merge pull request #3815 from amenonsen/typos

Fix some typos discovered during casual reading
Merge pull request #3814 from ftao/inventory_dir_abs

fix inventory.basedir is not absolute path when hostfile is startswith "./"
Merge pull request #3818 from resmo/feature/docsite-update

update docsite about new variable inventory_file
Merge pull request #3784 from drewblas/devel

Added git disclaimer about dealing with ssh host checking
Add missing version_added to docs.