NullPointerException on inputNumberSpinner RF 4.3.0-SNAPSHOT

gistfile1.txt

```
<rich:inputNumberSpinner value="50">
```

Throws 

```
17:13:56,046 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/aws-web].[Faces Servlet]] (http--0.0.0.0-8080-4) "Servlet.service()" pour la servlet Faces Servlet a généré une exception: java.lang.NullPointerException
	at org.richfaces.renderkit.html.InputNumberSpinnerRenderer.convertToBoolean(InputNumberSpinnerRenderer.java:138) [richfaces-components-ui-4.3.0-20120704.042959-78.jar:4.3.0-SNAPSHOT]
	at org.richfaces.renderkit.html.InputNumberSpinnerRenderer.doEncodeEnd(InputNumberSpinnerRenderer.java:175) [richfaces-components-ui-4.3.0-20120704.042959-78.jar:4.3.0-SNAPSHOT]
	at org.richfaces.renderkit.RendererBase.encodeEnd(RendererBase.java:175) [richfaces-components-ui-4.3.0-20120704.042959-78.jar:4.3.0-SNAPSHOT]
	at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1764) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
	at javax.faces.render.Renderer.encodeChildren(Renderer.java:168) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
	at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:845) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1757) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
	at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1760) [jboss-jsf-api_2.1_spec-2.0.0.Final.jar:2.0.0.Final]
```

Adding disableBrowserAutoComplete corrects this issue.

Seems similar to https://issues.jboss.org/browse/RF-12327