Be more strict on which SNMP interfaces must be merged while running the upgrade tool
Fix for NMS-6275 - thresholdFilter is ignored if value is null, despite AND condition
Fix for NMS-6278 - Threshold filters based on numeric values are not working when they are not part of the expression or ds-name
Added getWriteLock() syncs to the class to synchronize writes to the config.
These missing locks were causing ConcurrentModificationExceptions inside
Collectd. Fixes bug NMS-6277.
Fix for NMS-6278 Part II - Fixing failing tests.

The applyThresholds method from ThresholdingSet should check the
required datasources used on the expression, not all the datasources
involved on the threshold (which includes the filter attributes).
Fix for NMS-6278 Part III - Fixing failing tests.

The method thresholdEntity.getRequiredDatasources() returns all the
required data sources (from the expression and the filters).

The method thresholdEntity.getThresholdConfig().getRequiredDatasources()
returns only the datasources used on the expression, which is what the
deprecated SnmpThresholder and the JMXThresholder expects to use.
Fixed bug NMS-6279 by adding synchronized() blocks around all access to List
fields inside ThresholdingSet.
Cleaned up EventUtils.toString() method.
Fixed stack trace in bug NMS-6280 by throwing FileNotFoundException when
the label of the resource cannot be calculated. Cleaned up label calculation
code inside CollectionResourceWrapper.
Merge branch '1.10' into 1.12

Conflicts:
	opennms-dao/src/main/java/org/opennms/netmgt/config/collector/ResourceIdentifier.java
	opennms-services/src/main/java/org/opennms/netmgt/collectd/IfInfo.java
	opennms-services/src/main/java/org/opennms/netmgt/collectd/PersistOperationBuilder.java
	opennms-services/src/main/java/org/opennms/netmgt/config/PollOutagesConfigManager.java
	opennms-services/src/main/java/org/opennms/netmgt/threshd/CollectionResourceWrapper.java
	opennms-services/src/main/java/org/opennms/netmgt/threshd/ThresholdingSet.java
	opennms-services/src/main/java/org/opennms/netmgt/threshd/ThresholdingVisitor.java
Merge branch '1.12'

Conflicts:
	opennms-services/src/main/java/org/opennms/netmgt/collectd/IfInfo.java
	opennms-services/src/main/java/org/opennms/netmgt/collectd/SnmpCollectionResource.java
	opennms-services/src/main/java/org/opennms/netmgt/threshd/CollectionResourceWrapper.java
	opennms-services/src/main/java/org/opennms/netmgt/threshd/ThresholdingSet.java
	opennms-services/src/main/java/org/opennms/netmgt/threshd/ThresholdingVisitor.java