[#58637350] Don't use set -u in wrapper script
[#58637350] Don't use set -u in wrapper script

It seems that virtualenv doesn't like this. Sad face.

Installing pip...............done.
.venv/bin/activate: line 6: _OLD_VIRTUAL_PATH: unbound variable
Build step 'Execute shell' marked build as failure
Finished: FAILURE

lukaszraczylo/router,alphagov/router,lukaszraczylo/router