be puppet-lint friendly

puppet-lint raises a warning when strings <code>'true'</code> or <code>'false'</code> are used instead of simply <code>true</code> and <code>false</code>.

This patch allows the user to use a <b>boolean</b> for the parameter <code>autorestart</code> (in addition to the strings <code>'true'</code>, <code>'false'</code> and <code>'unexpected'</code>)

No change needed in the templates as <code><%= true %></code>  and <code> <%= 'true' %></code> have the same output.
I think you should use !validate_bool here.