Issue while running patstim test on GPU from testcorenrn repository  #503

$ ./x86_64/special-core -e 100 -d coredat --gpu --mpi --pattern patstim.spk
 num_mpi=1
 num_omp_thread=2

 Info : 4 GPUs shared by 1 ranks per node

 Duke, Yale, and the BlueBrain Project -- Copyright 1984-2020
 Version : 0.21.0 f2e152b (2021-03-04 00:45:29 +0100)

 Additional mechanisms from files
 Gfluct3.mod exp2syn.mod expsyn.mod hh.mod hhderiv.mod hhkin.mod hhwatch.mod nacum.mod netstim.mod passive.mod pattern.mod stim.mod svclmp.mod vecevent.mod

 Memory (MBs) :             After mk_mech : Max 217.5625, Min 217.5625, Avg 217.5625
 Memory (MBs) :            After MPI_Init : Max 217.5625, Min 217.5625, Avg 217.5625
 Memory (MBs) :          Before nrn_setup : Max 218.5898, Min 218.5898, Avg 218.5898
 WARNING : GPU execution requires --cell-permute type 1 or 2. Setting it to 1.
 Setup Done   : 0.00 seconds
 Model size   : 10.96 kB
 Memory (MBs) :          After nrn_setup  : Max 226.6172, Min 226.6172, Avg 226.6172
GENERAL PARAMETERS
--mpi=true
--gpu=true
--dt=0.025
--tstop=100

GPU
--nwarp=0
--cell-permute=0

.......

 psolve |========================================================| t: 100.00 ETA: 0h00m01s

Solver Time : 1.45126
FATAL ERROR: variable in OpenACC API data update in routine was not found on the GPU