Revert "Redefine LIBMESH_CHKERR(2) to avoid breaking MOOSE..."

This reverts commit fb0abb5.

Author: nmnobre

include/numerics/petsc_solver_exception.h

@@ -89,10 +89,6 @@ class PetscSolverException : public SolverException
     LIBMESH_CHKERRQ(ierr);                      \
   } while (0)
 
-// Remove me: for backward compatibility with MOOSE only
-#define LIBMESH_CHKERR(ierr) LIBMESH_CHKERRQ(ierr)
-#define LIBMESH_CHKERR2(comm, ierr) LIBMESH_CHKERRA(comm, ierr)
-
 #else
 
 // If we don't have exceptions enabled, just fall back on calling