Change httpd Keystone log to keystone.log

The normal extension for log files is .log. Log rotation should
work because the extension is as expected.

Change-Id: Ia5e42ea9d953e8395b86ab58cdef6c2d852efc94
Related-Bug: #1359995
diff --git a/files/apache-keystone.template b/files/apache-keystone.template
index fc8731c..7954a86 100644
--- a/files/apache-keystone.template
+++ b/files/apache-keystone.template
@@ -6,7 +6,7 @@
     WSGIProcessGroup keystone-public
     WSGIScriptAlias / %PUBLICWSGI%
     WSGIApplicationGroup %{GLOBAL}
-    ErrorLog /var/log/%APACHE_NAME%/keystone
+    ErrorLog /var/log/%APACHE_NAME%/keystone.log
     LogLevel debug
     CustomLog /var/log/%APACHE_NAME%/access.log combined
 </VirtualHost>
@@ -16,7 +16,7 @@
     WSGIProcessGroup keystone-admin
     WSGIScriptAlias / %ADMINWSGI%
     WSGIApplicationGroup %{GLOBAL}
-    ErrorLog /var/log/%APACHE_NAME%/keystone
+    ErrorLog /var/log/%APACHE_NAME%/keystone.log
     LogLevel debug
     CustomLog /var/log/%APACHE_NAME%/access.log combined
 </VirtualHost>