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/autotoolsprojectmanager/autotoolsproject.cpp

@@ -148,11 +148,6 @@ AutotoolsTarget *AutotoolsProject::activeTarget() const
     return static_cast<AutotoolsTarget *>(Project::activeTarget());
 }
 
-QList<Project *> AutotoolsProject::dependsOn()
-{
-    return QList<Project *>();
-}
-
 QString AutotoolsProject::defaultBuildDirectory() const
 {
     return projectDirectory();