Add logic to work with old and new mysql module

This patch uses the load_module_metadata function to check whether the
mysql module has a metadata.json file. If it does, we can assume it's
new enough to support the new interface. If not, use the old one.

Change-Id: I3ff754b15eef51c3c86c188647353a4a1d3bfea0
Depends-On: Ia366c0f7f1bfbfa843071e733a5b0a96873a60d8

manifests/init.pp

@@ -37,6 +37,8 @@ class nodepool (
 ) {
 
 
+  $mysql_data = load_module_metadata('mysql', true)
+  if $mysql_data == {} {
     class { '::mysql::server':
       config_hash => {
         'root_password'  => $mysql_root_password,
@@ -44,6 +46,16 @@ class nodepool (
         'bind_address'   => '127.0.0.1',
       }
     }
+  } else { # If it has metadata.json, assume it's new enough to use this interface
+    class { '::mysql::server':
+      root_password    => $mysql_root_password,
+      override_options => {
+        'mysqld' => {
+          'default-storage-engine' => 'InnoDB',
+        }
+      },
+    }
+  }
 
   include ::mysql::server::account_security