fix image alert for remote images (#91)
fix image alert for remote images (#91)

* fix image alert for remote images

What's fixed:
1. key for image location is 'locations', not 'location'
2. one image may have multiple locations.
3. only all locations are remote means it's an remote image.  That means
if one of the locations is 'file', it's not a remote image.

blueboxgroup/ursula-monitoring,aacole/ursula-monitoring,blueboxgroup/ursula-monitoring,blueboxgroup/ursula-monitoring,aacole/ursula-monitoring,aacole/ursula-monitoring,aacole/ursula-monitoring,blueboxgroup/ursula-monitoring