Tasks which delegate from a container to a container on a separate host
currently fail because the 'physical_host_addr' variable, which those
tasks use to connect to a physical host, is exclusively set as the
address of the originating container's physical host.
Assign a new host variable, 'physical_host_addrs', which contains a
mapping of each physical host and its address, so the tasks can now
lookup of the correct address to use depending on the target container.
Change-Id: If594914df53efacc6d5bba148f4f46280f5a117d
8b1a07d2d6