ProjectExplorer: Replace BuildConfigurationFactory::availableBuilds

... by a function object.

Change-Id: I9953ba6915c0177e7c4067d36dd755fc2ba5cf84
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/compilationdatabaseprojectmanager/compilationdatabaseproject.h

@@ -100,10 +100,6 @@ class CompilationDatabaseBuildConfigurationFactory
     Q_OBJECT
 public:
     CompilationDatabaseBuildConfigurationFactory();
-
-    QList<ProjectExplorer::BuildInfo> availableBuilds(const ProjectExplorer::Kit *k,
-                                                      const Utils::FilePath &projectPath,
-                                                      bool forSetup) const override;
 };
 
 } // namespace Internal