Simplify code to set up output parser chain a bit

It is save to set 0 as a parser.

Change-Id: I57e9a6e2c3c4661356b5b79371946edad367888a
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/projectexplorer/processstep.cpp

@@ -88,9 +88,7 @@ bool ProcessStep::init()
     pp->setArguments(m_arguments);
     pp->resolveAll();
 
-    IOutputParser *parser = target()->kit()->createOutputParser();
-    if (parser)
-        setOutputParser(parser);
+    setOutputParser(target()->kit()->createOutputParser());
     return AbstractProcessStep::init();
 }