Fix apache response time casting from us to s

Change-Id: I3d546728a93ce95504f5550d9daaf5f45299b6be
Partial-Fix: PROD-20999
diff --git a/ceilometer/meta/fluentd.yml b/ceilometer/meta/fluentd.yml
index d5d868e..bbf25df 100644
--- a/ceilometer/meta/fluentd.yml
+++ b/ceilometer/meta/fluentd.yml
@@ -43,8 +43,9 @@
                 value: INFO
               - name: programname
                 value: ceilometer-wsgi
+                # Apache logs response time in microseconds
               - name: http_response_time
-                value: ${ record['http_response_time'].to_i/100000.to_f }
+                value: ${ record['http_response_time'].to_i/10**6.to_f }
         match:
           send_to_default:
             tag: openstack.ceilometer