Use http://socket=<path>/path to use the local Unix domain socket

Previously we used file:///path/to/socket but this prevented us
from having an HTTP path in the URI (e.g. /VM/export/xvda etc)

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
HTTP client: support URIs with basic auth

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Regenerate OASIS

Signed-off-by: David Scott <dave.scott@eu.citrix.com>