CLOUDIFY-2528 get machine ip from runtime properties and raise error if ip doesn't exist
CLOUDIFY-2528 dont get ip from runtime properties if ctx is not of a node
CLOUDIFY-2528 initialize ip with None value
Merge pull request #16 from CloudifySource/feature/CLOUDIFY-2528-uninstall-continue-on-failure

CLOUDIFY-2528 get machine ip from runtime properties and raise error if ...