Replace Device::SetProperties with 'nested' version
Previous implementation expected dictionary in form:
{ 'package.name' : 'new_value' }
new version expects:
{ 'package': {'name' : 'new_value'}}
BUG:24267885
Change-Id: I14ae43b7094e12a49433f16a5afa9e20bd5bccb1
Reviewed-on: https://weave-review.googlesource.com/1254
Reviewed-by: Vitaly Buka <vitalybuka@google.com>