Remove Project::dependsOn(), it's never called

I don't remember why I did leave it alone in the reafctoring some years
ago, but surely it serves no purpose.

Change-Id: Idf920faf3f8f7128cd410501f2c3748e100dfbfb
Reviewed-by: Tobias Hunger <tobias.hunger@nokia.com>

src/plugins/qt4projectmanager/qt4project.cpp

@@ -911,12 +911,6 @@ QString Qt4Project::generatedUiHeader(const QString &formFile) const
     return QString();
 }
 
-QList<ProjectExplorer::Project*> Qt4Project::dependsOn()
-{
-    // NBS implement dependsOn
-    return QList<Project *>();
-}
-
 void Qt4Project::proFileParseError(const QString &errorMessage)
 {
     Core::ICore::messageManager()->printToOutputPanePopup(errorMessage);