Format of nova-api log files was corrected

When nova-api and nova-ec2-api services are started by Apache
(it can be done with devstack config option NOVA_USE_MOD_WSGI=True)
log files contained duplication of timestamp value.

Change-Id: I5439ea8f89ca3073600456f67220e9d3f5257d97
Closes-Bug: #1510517
diff --git a/files/apache-nova-api.template b/files/apache-nova-api.template
index 4908152..bcf406e 100644
--- a/files/apache-nova-api.template
+++ b/files/apache-nova-api.template
@@ -7,7 +7,7 @@
     WSGIApplicationGroup %{GLOBAL}
     WSGIPassAuthorization On
     <IfVersion >= 2.4>
-      ErrorLogFormat "%{cu}t %M"
+      ErrorLogFormat "%M"
     </IfVersion>
     ErrorLog /var/log/%APACHE_NAME%/nova-api.log
     %SSLENGINE%