fix to formatter when time annotation is missing

eu.fbk.tools.editor/eu.fbk.tools.editor.nusmv/src/eu/fbk/tools/editor/nusmv/formatting2/NuSMVFormatter.xtend

@@ -29,7 +29,7 @@ class NuSMVFormatter extends AbstractFormatter2 {
 				 
 		for (module : model.getModules()) {
 			
-			if( model.annotation.value !== null ) // trick because call to model.annotation.format seems not working
+			if( model.annotation!== null && model.annotation.value !== null ) // trick because call to model.annotation.format seems not working
 			{
 				module.surround[newLine].format			
 			}