ProjectExplorer: Simplify use of AbstractProcessStep::init()

1. Systematically check for AbstractProcessStep::init() first in
   derived classes.
2. Use setupProcessParameters(processParameters()); by default in
   the base implementation.
3. Drop all re-implementations that are effectively the same.

Change-Id: I0ae54dd4909b354672a63ee56d0b7c2ea0732494
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/autotoolsprojectmanager/configurestep.cpp

@@ -82,7 +82,6 @@ public:
     void setAdditionalArguments(const QString &list);
 
 private:
-    bool init() override;
     void doRun() override;
 
     ProjectExplorer::StringAspect *m_additionalArgumentsAspect = nullptr;
@@ -123,14 +122,6 @@ ConfigureStep::ConfigureStep(BuildStepList *bsl, Utils::Id id)
     });
 }
 
-bool ConfigureStep::init()
-{
-    ProcessParameters *pp = processParameters();
-    setupProcessParameters(pp);
-
-    return AbstractProcessStep::init();
-}
-
 void ConfigureStep::doRun()
 {
     //Check whether we need to run configure