Readd debug guard

Author: BryanMLima

server/src/main/java/com/cloud/agent/manager/allocator/impl/FirstFitAllocator.java

@@ -133,7 +133,9 @@ public List<Host> allocateTo(VirtualMachineProfile vmProfile, DeploymentPlan pla
 
         String paramAsStringToLog = String.format("zone [%s], pod [%s], cluster [%s]", dcId, podId, clusterId);
 
-        s_logger.debug(String.format("Looking for hosts in %s.", paramAsStringToLog));
+        if (s_logger.isDebugEnabled()) {
+            s_logger.debug(String.format("Looking for hosts in %s.", paramAsStringToLog));
+        }
 
         String hostTagOnOffering = offering.getHostTag();
         String hostTagOnTemplate = template.getTemplateTag();