Honor ansible_private_key_file for delegated hosts

If a delegated host is not found in the inventory specified
private_key_file for primary host was not used.

This allows running playbooks without having to define any inventory at
all and to use the same ssh private key for both primary host and
delegated one.
Merge pull request #2 from taylorbarstow/inventorytree-tests

Adding unit tests for host groups with inventory dir
Adds support for VPC subnets to ELB
module docker_image - default tag latest

Fix constant rebuild of image if no tag specified.
Determine selinux context for NFS mount points correctly

Fixes #7009
Fix for https://github.com/ansible/ansible/issues/7054 - when renaming an instance and waiting for the change to occur, force result.id to the name of the new instance so the subsequent call to get_current_resource succeeds.
Make sure umask is set restrictively before creating any vault files
Fix #7057 missing False default for vars_prompt

The test for default should be "is not None" since a boolean value of
False is a valid value.

See discussion at:
  https://groups.google.com/forum/#!topic/ansible-project/oc1_zE-FnyI
Updating changelog/releases/packaging for 1.5.5 release
Make sure HostVars object is instantiated before assigning it

Fixes #7006
Fix date in changelog for RPM builds off devel branch.
Merge branch 'issue_7009_nfs_selinux' into devel
Enhance error message about missing ControlPersist

ansible_ssh_args is good for playbook, but in the ~/.ansible.cfg
file, it should be ssh_args in a specific section.
Clean a bit more the ssh_args configuration

If someone add ssh_args = " " to his .ansible.cfg, it will result into
strange failure later :

    <server.example.org> ESTABLISH CONNECTION FOR USER: misc
    <server.example.org> REMOTE_MODULE ping
    <server.example.org> EXEC ['ssh', '-C', '-tt', '-q', ' ', '-o', 'KbdInteractiveAuthentication=no',
    '-o', 'PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey', '-o', 'PasswordAuthentication=no',
    '-o', 'ConnectTimeout=10', 'server.example.org', "/bin/sh -c 'mkdir -p /tmp/ansible-tmp-1397947711.21-5932460998838
    && chmod a+rx /tmp/ansible-tmp-1397947711.21-5932460998838 && echo /tmp/ansible-tmp-1397947711.21-5932460998838'"]
    server.example.org | FAILED => SSH encountered an unknown error during the connection. We recommend you re-run the
    command using -vvvv, which will enable SSH debugging output to help diagnose the issue

The root cause is the empty string between -q and -o, who kinda break mkdir.
fixed ETIME issue on FreeBSD 8 through 10, which broke all fact
gathering
ifconfig changed on FreeBSD, tested this on 8,9 and 10 latest stable
versions and it now works
Improve error message when multiple action are given

This can be illustrated using this playbook:

    - command: id
      delegate_to: "{{ remote_server }}"
      user: "{{ remote_user }}"

The error is to use 'user' instead of 'remote_user', but the error message
do not really mention it, so it can be a bit hard to spot.
Add an example to show all hostvars using debug

This is a useful example to help debug how facts and vars are being collated.
Explicit check of return code for autoinstallation of python-apt added

This will allow easier debugging through more meaningful error message.
Merge pull request #7081 from bcoca/freebsd_fact_fix

fixed ETIME issue on FreeBSD 8 through 10, which broke fact gather