devstack assumes obsoleted docker API v1.3

This is a nova-docker issue when using devstack to install nova-docker.

Devstack installs Docker (extras.d/70-docker.sh) and then verifies this by sending a http GET:
      `echo -e 'GET /v1.3/version HTTP/1.0\n\n' | socat - unix-connect:$DOCKER_UNIX_SOCKET 2>/dev/null | grep -q '200 OK'`
The version of Docker currently being installed is Server version: 1.7.1 Server API version: 1.19 which returns an error when devstack attempts to use API version 1.3 (above GET command).

Newer Docker daemon (1.7.1) returns an error:
    HTTP/1.0 400 Bad Request
    Content-Type: text/plain; charset=utf-8
    Date: Tue, 25 Aug 2015 17:53:09 GMT...

devstack is expecting the response to include the string "200 OK" as seen in the grep above. This causes the devstack nova-docker stack.sh install to fail.

Possible solutions include:
   (1) Forcing an older tested version (e.g.1.5.0) of Docker for the install_package and is_package_installed() test in function install_nova_hypervisor. This option may ignore any benefits of the newer Docker package.
   (2) Fixing the devstack scripts to use the newer Docker http API versions. If newer Docker package versions are used testing for other unintended consequences would seem appropriate too.

The temp fix using option (1) works with the following two lines is devstack scripts changed:

stack@Steve-Kilo-Compute-Docker:~$ grep -R -n lxc-docker devstack/*
devstack/extras.d/70-docker.sh:48: install_package --force-yes lxc-docker-1.5.0 socat
devstack/lib/nova_plugins/hypervisor-docker:89: if ! ( is_package_installed docker-1.5.0 || is_package_installed docker-io-1.5.0 || is_package_installed lxc-docker-1.5.0 ) ; then
stack@Steve-Kilo-Compute-Docker:~$
-------------------
Steve Adams
<email address hidden>
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