Fix to prevent rules from being cached between Jenkins builds even if suppression file is not specified.

Former-commit-id: 860fded462d768acb207ebe35464936d7f80f59c

dependency-check-core/src/main/java/org/owasp/dependencycheck/analyzer/AbstractSuppressionAnalyzer.java

@@ -93,6 +93,7 @@ public abstract class AbstractSuppressionAnalyzer extends AbstractAnalyzer {
     private void loadSuppressionData() throws SuppressionParseException {
         final String suppressionFilePath = Settings.getString(Settings.KEYS.SUPPRESSION_FILE);
         if (suppressionFilePath == null) {
+            rules = null; // Set to null to fix issue with Jenkins plugin configuration changes between builds
             return;
         }
         File file = null;