Make sure that token flush's maxdelay is a numeric value

If this is given something else than a number, it will add an erroneous
value to the cron job and it'll fail.

Depends-On: I00823e23358df91ce54f421c12636f05d4196e15
Change-Id: Iccb1958d0237ec4105c30e08db86e28cc630d08b
Closes-Bug: #1708584

manifests/cron/token_flush.pp

@@ -54,15 +54,15 @@
 #    Allow to run the crontab on behalf any user.
 #
 class keystone::cron::token_flush (
-  $ensure      = present,
-  $minute      = 1,
-  $hour        = '*',
-  $monthday    = '*',
-  $month       = '*',
-  $weekday     = '*',
-  $maxdelay    = 0,
-  $destination = '/var/log/keystone/keystone-tokenflush.log',
-  $user        = 'keystone',
+  $ensure           = present,
+  $minute           = 1,
+  $hour             = '*',
+  $monthday         = '*',
+  $month            = '*',
+  $weekday          = '*',
+  Integer $maxdelay = 0,
+  $destination      = '/var/log/keystone/keystone-tokenflush.log',
+  $user             = 'keystone',
 ) {
 
   include ::keystone::deps