Handling spurious log for last start updates when the last start is not changed (faucetsdn#1117)

Author: jainrocks

udmis/src/main/java/com/google/bos/udmi/service/access/IotAccessBase.java

@@ -233,7 +233,10 @@ public String modifyConfig(Envelope envelope, Function<Entry<Long, String>, Stri
           debug("Retrieved config %s/%s #%d", registryId, deviceId, version);
           String updatedConfig = ifNotNullGet(safeMunge(munger, currentConfig),
               updated -> checkedUpdate(envelope, version, updated));
-          debug("Applied config %s/%s #%d", registryId, deviceId, version);
+          // Preventing a spurious "applied config" message when no changes occurred.
+          if (updatedConfig != null) {
+            debug("Applied config %s/%s #%d", registryId, deviceId, version);
+          }
           return updatedConfig;
         } catch (AbortLoopException e) {
           throw e;