disabling writediagfi when runnning the mesoscale

[emillour]

When running the mesoscale, one should not try to write diagfi files.
Thus in some places of the code there are added cpp wrappers around calls to writediagfi, e.g. watercloud_mod.F90:

#ifndef MESOSCALE
c=======================================================================
      call WRITEDIAGFI(ngrid,"pdqice2","pdqcloudice apres microphysique"
     &      ,"kg/kg.s-1",3,pdqcloud(1:ngrid,1:nlay,igcm_h2o_ice))
...
#endif

But in many cases when calls to writediafi are added throughout the code they are not "protected" by #ifndef MESOSCALE

A probably less cumbersome way could be to handle within writediagfi whether it is called in "mesoscale" (in which case an early exit from the routine should do the trick) or "gcm" context.