change elpa set handle so it will only call once not in every ion step

[pplab]

No description provided.

[pplab]

Modified files:

• src_pdiag/pdiag_double.cpp

  Now only set elpa handle once, because setting the same elpa handle in every ion step may cause the program to collapse

  Require more tests

• src_io/write_wfc_realspace.cpp
  some compilers can not accept the space after \ at the end of the line