Move log statement to expose actually info_cache value

When debugging an info_cache issue I noticed the logs  display:

"Updating cache with info: None update_instance_cache_with_nw_info"

Though we are not actually updating the info_cache with None as if
nw_info is not isinstance(NetworkInfo we fetch the latest nw_info
from neturon. This patch just moves the log statement so the actual
value is exposed.

Change-Id: I3a74191c31a053682bb2558c59228025ceb0cf28
Closes-bug: 1292298
Remove aggregate_get() from conductor API

The aggregate_get() method of the conductor API is no longer used.
Remove it from the client code and leave a note on the manager side
for it to be removed in the next major version bump.

This is cleanup, but part of a blueprint being completed during
feature freeze.  It allows us to drop more code in the rpc version
bump.

Part of blueprint rpc-major-version-updates-icehouse

Change-Id: I893f58bbcae21112f186348cefcbfdd3bcbb8c06
Merge "Move log statement to expose actually info_cache value"
Merge "Remove aggregate_get() from conductor API"