[Core] Log missing jar manifest at trace level

Author: alexrobin

sensorhub-core/src/main/java/org/sensorhub/utils/ModuleUtils.java

@@ -115,7 +115,7 @@ public static Manifest getManifest(Class<?> clazz)
         }
         catch (IOException e)
         {
-            log.debug("Cannot access JAR manifest for {}", clazz);
+            log.trace("Cannot access JAR manifest for {}", clazz);
         }
 
         return null;