cmCommand: remove unused methods from interface and all implementations

Source/cmFindProgramCommand.h

@@ -37,11 +37,6 @@ public:
   bool InitialPass(std::vector<std::string> const& args,
                    cmExecutionStatus& status) CM_OVERRIDE;
 
-  /**
-   * The name of the command as specified in CMakeList.txt.
-   */
-  std::string GetName() const CM_OVERRIDE { return "find_program"; }
-
 private:
   std::string FindProgram();
   std::string FindNormalProgram();