Fix coprocessing py script typo
A bug was introduced recently in !2459 (merged) that produces errors when using
coprocessor.py script. This MR fixes the bug.
Note: Unfortunately, the tests on the Catalyst examples pass whereas those errors happen. We will have to make sure this won't happen anymore.
Traceback (most recent call last): File "<string>", line 2, in <module> File "feslicescript.py", line 75, in RequestDataDescription File "/home/joachim/dev/paraview-build/lib/python3.6/site-packages/paraview/coprocessing.py", line 181, in LoadRequestedData datadescription.GetInputDescriptionByName(writerinputinput).AllFieldsOn() NameError: name 'writerinputinput' is not defined