Removed notes_url from nagios host extra info

We populate a notes_url attribute for host extra info which creates
an extra link on extended host info icinga pages to ganglia. In order to
implement this information from the ganglia module was used. At the same
time it is emitting some Puppet 3 deprecation warnings. Try to remove
this and evaluate the situation.

Change-Id: I1d4d864b18106e8d964bdb28297c420391d0bba1
Merge "Removed notes_url from nagios host extra info" into production