setvalue/xforms-value-changed with empty calculation column not working

[MartijnR]

tbc if Enketo or Pyxform issue

[MartijnR]

• [x] create minimal test form -> https://docs.google.com/spreadsheets/d/1x4AphUIumvMjdjKNwNvHTKoFiLLXXUgvpVk1Yj7i1XI/edit#gid=0
• file bug report in pyxform
• [x] in enketo-transformer set a missing value attribute to "" -> https://github.com/enketo/enketo/issues/785
• [x] test in http://localhost:8005/?xform=oc-351-setvalue.xml

[MartijnR]

• [ ] mark as ready once enketo-transformer updates (1.40.3 or higher) have propagated tot this repo

[pbowen-oc]

We will hold off on this until our current validation process is closer to completed.