ProjectExplorer: Remove arguments from node change signals

This discourages storing the pointers needlessly. The items
are still easy accessible by the static ProjectTree::currentNode()

Change-Id: I3c0cd019e9fdc382afacbc9d9de3b97d5f58ae1e
Reviewed-by: Tobias Hunger <tobias.hunger@qt.io>

src/plugins/qmakeprojectmanager/qmakeprojectmanagerplugin.h

@@ -33,9 +33,7 @@ class QAction;
 QT_END_NAMESPACE
 
 namespace ProjectExplorer {
-class Node;
 class Project;
-class KitInformation;
 class Target;
 }
 namespace Utils { class ParameterAction; }
@@ -69,7 +67,7 @@ private:
     void projectChanged();
     void activeTargetChanged();
     void updateRunQMakeAction();
-    void updateContextActions(ProjectExplorer::Node *node, ProjectExplorer::Project *project);
+    void updateContextActions();
     void buildStateChanged(ProjectExplorer::Project *pro);
     void updateBuildFileAction();