agent: missing log message parameters

Fix a missing log message parameter, causing the agent to fail if it
detects that the vm should be migrated away to a better host

Change-Id: Icb5bd3bd46b63ecbeeb8e1d0fdc8ca9b2c9e0f23
Bug-Url: https://bugzilla.redhat.com/1014112
Signed-off-by: Greg Padgett <gpadgett@redhat.com>