Disable monitoring when destroying machine or deleting backend

Either directly (when in io/core) context or through API request
in case of standalone io.
Fix weird bug with sudo output redirection in deploy_collectd

In some machines (experienced it in an ec2 AMI vm), doing something
like:
  $sudo echo hello > /tmp/1
will fail with a 'permission denied error', whereas
  $sudo su -c "echo hello > tmp/1"
succeeds. WTF!
Merge pull request #94 from mistio/disable_monitoring_fixes

Disable monitoring fixes