Fixing bug with unstructured grid ghost cell generator.

Andrew Bauerrequested to merge
acbauer/vtk:fix_unstructuredghostcellsgenerator into master

Issue was with not keeping memory unmodified for unblocking sends until send was checked to make sure it completed.

Addresses paraview/paraview#18175 (closed).

Backport: paraview/release

Edited by Andrew Bauer

Merge request reports