CRM-19651 Event location tab reports that other events use a unique address

When looking at the location tab of an event, even if a totally new location is entered, the following message appears: "This location is used by 1 other events. Modifying location information will change values for all events." This statement is not true.

It appears that this message always reports one more event using the location than is actually the case. i.e. if it's used in one other event, it will report 2, etc.

Expected behaviour:
1. The message is not displayed at all if no other events use that location
2. If other events use the same location, the correct number of events is reported. Actually, that's not really very helpful even if the number is correct, because it doesn't say WHICH events. Maybe the message should be static and say something like "This location is used by other event(s)...."