Bug - double allocate

[tclune]

The attached reproducer from @bena-nasa shows that the recent workaround for a gfortran memory leak unfortunately introduced a bug in the vector set() method. Previously the scenario in this reproducer relied on intrinsic assignment which was implicitly deallocating in this scenario. The memory workaround used explicit allocation and it was not obvious that a check needed to be done for deallocation.

I think the fix will be easy, but a bit ugly.

use pfio
   implicit NONE
 
   type(Variable) :: v, v1, v2
   type(StringVariableMap) :: vars
 
   v = variable(pfio_real32,dimensions='time')
   call v%add_attribute('long_name','time')
 
   v1 = variable(pfio_real32,dimensions='time')
   call v%add_attribute('long_name','time1')
 
   v2 = variable(pfio_real32,dimensions='lon')
   call v%add_attribute('long_name','longitude')
 
   call vars%insert('time',v1)
   call vars%insert('lon',v2)
 
   call vars%set('time',v)
 
End Program test_modify

(Note the reproducer is using code from GEOS-ESM/MAPL.