Turn off enspread reg (#635)

In cplr_get_fv3_regional_ensperts.f90, "write_ens_sprd=.true." is
hard-coded and overwrites the values in namelist.
write_ens_sprd=.true." should be removed.

Fixes #634 

**Type of change**

Please delete options that are not relevant.

- [x] Bug fix (non-breaking change which fixes an issue)

src/gsi/cplr_get_fv3_regional_ensperts.f90

@@ -684,7 +684,6 @@ subroutine get_fv3_regional_ensperts_run(this,en_perts,nelen,ps_bar)
 
     enddo ! it 4d loop
  ! CALCULATE ENSEMBLE SPREAD
-    write_ens_sprd=.true.
     if(write_ens_sprd ) then
         call this%ens_spread_dualres_regional(mype,en_perts,nelen)
         call mpi_barrier(mpi_comm_world,ierror) ! do we need this mpi_barrier here?