Add missing inherit for puppetdb::params

Prior to this commit if you tried to use the class
`puppetdb::master::puppetdb_conf` directly (rather than
implicitly through `puppetdb::master::config`), you would
get a failure about `puppetdb::params` not having been
evaluated.  This is because the class was missing an
`inherits` statement; this commit fixes the bug.

manifests/master/puppetdb_conf.pp

@@ -26,7 +26,7 @@ class puppetdb::master::puppetdb_conf(
   $server         = 'localhost',
   $port           = '8081',
   $puppet_confdir = $puppetdb::params::puppet_confdir,
-) {
+) inherits puppetdb::params {
 
   Ini_setting {
     ensure  => present,