No timeout for API to registry requests

[Stuart McLaren]

When the API server creates a registry client there is no way to specify a timeout value.

This means that if the registry process to which the API is connected locks up for some reason
the API will wait indefinitely (at least until the system-wide tcp settings kick in.)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/17936

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/17936
Committed: http://github.com/openstack/glance/commit/a12f09fa96e3798afdf340b4f3215b0b25b1db27
Submitter: Jenkins
Branch: master

commit a12f09fa96e3798afdf340b4f3215b0b25b1db27
Author: Stuart McLaren <email address hidden>
Date: Wed Dec 12 13:25:20 2012 +0000

    Add registry_client_timeout parameter

    Add a "registry_client_timeout" parameter which specifies the
    time, in seconds, that an API server will wait for a registry
    request to complete.

    This prevents API clients hanging indefinitely in the event
    that the registry becomes unresponsive.

    Addresses LP bug 1089391.

    Change-Id: Ib27b6eecdcb65cbe644c156a0ca5cd0d0b4638dd