Corrected bug in obs_sen_is4dvar.h

[arango]

Several indices were not initialized in obs_sen_is4dvar.h when activating IS4DVAR_SENSITIVITY. We need to add:

       DO ng=1,Ngrids
#if defined ADJUST_BOUNDARY || defined ADJUST_STFLUX || \
    defined ADJUST_WSTRESS
        Lfinp(ng)=1         ! forcing index for input
        Lfout(ng)=1         ! forcing index for output history files
#endif
#ifdef ADJUST_BOUNDARY
        Lbinp(ng)=1         ! boundary index for input
        Lbout(ng)=1         ! boundary index for output history files
#endif
        ...
      END DO

Many thanks to Andy Moore and the 4D-Var training class for bringing this to my attention.