fix the mock bug of ddot function

Author: pxlxingliang

source/src_pw/test/diago_david_test.cpp

@@ -1,5 +1,4 @@
 #include"../diago_david.h"
-#include"../diago_cg.h"
 #include"./diago_mock.h"
 #include"gtest/gtest.h"
 #include"mpi.h"
@@ -28,9 +27,6 @@
  *  
  */
 
-//mock the ddot_real function
-double Diago_CG::ddot_real(int const&, std::complex<double> const*, std::complex<double> const*, bool) {};
-
 //use lapack to calcualte eigenvalue of matrix hm
 //NOTE: after finish this function, hm stores the eigen vectors.
 void lapackEigen(int &npw, ModuleBase::ComplexMatrix &hm, ModuleBase::ComplexMatrix &ev,double * e, bool outtime=false)