ENG-6857: Initial defaultprocread for Jenkin.
ENG-6857: add catalog update to change group with flipping defaultprocread.
ENG-6857: refactor out decision making in one place.
ENG-6857: review changes.
ENG-6857: refactore more...
Merge pull request #1709 from VoltDB/ENG-6857

Eng 6857
Added a .gitignore file, in voltdb/tests/geb/studioWeb/, to tell git to
ignore the /build/ and /.gradle/ directories, and all their class files,
test reports, etc., that get generated when you run the GEB tests (e.g.,
via: ./gradlew firefox --rerun-tasks).