monitoring: Fetch Unmanaged nodes from db
monitoring: Fetch Unmanaged nodes from db

This patch fetches unmanaged nodes from db instead
of salt during system summary calculation.
The reason for this change are as follows:
1. This information is stored to db on the basis of
   minion event. so its ensured to be the latest.So,
   rather than going to salt, its better to get it
   from db.
2. This avoids any salt related failures.

Change-Id: I8f03f5b05ba9d479b1d7abf2b2724e46c31efd64
Signed-off-by: anmolbabu <3d38fb1e9c5ff2662fc415254efcdfedb95b84d5@gmail.com>

skyrings/skyring,skyrings/skyring,skyrings/skyring,skyrings/skyring