Minor correction to close_io.F and set_contact.F

[arango]

This update corrects minor issues in the following files:

• close_io.F: Ensure that the biology model header file is written into the bio_file global attribute in output NetCDF files. Many thanks to Aijun Zhang for bringing this problem to my attention.

• set_contact.F: Correct of the get_Vweights switch to accelerate nested computations. We need instead:

  !
  !  Set the switch to compute vertical interpolation weights. Currently,
  !  they are only needed in non-coincident composite grids.
  !
        IF (ANY(Lcoincident).or.ANY(Lcomposite)) THEN
          get_Vweights=.TRUE.
        ELSE
          get_Vweights=.FALSE.
        END IF
  

  Many thanks to Andy Moore for reporting this issue.