Check proper list for debug logging (#366)

pf4j/src/main/java/org/pf4j/AbstractExtensionFinder.java

@@ -63,7 +63,7 @@ public abstract class AbstractExtensionFinder implements ExtensionFinder, Plugin
             result.addAll(pluginExtensions);
         }
 
-        if (entries.isEmpty()) {
+        if (result.isEmpty()) {
             log.debug("No extensions found for extension point '{}'", type.getName());
         } else {
             log.debug("Found {} extensions for extension point '{}'", result.size(), type.getName());