fix venv/postBuild test

- switch to simpler jupyter-keepalive extension
- set -e in postBuild to catch errors
- set -x to see steps as they go for easier debugging

Author: minrk

tests/venv/postBuild/postBuild

@@ -1,4 +1,6 @@
 #!/bin/bash
-jupyter server extension disable --sys-prefix jupyter_collaboration
+set -ex
+
+jupyter server extension disable --sys-prefix jupyter_keepalive
 npm install --global configurable-http-proxy
 npm cache clean --force

tests/venv/postBuild/requirements.txt

@@ -1 +1 @@
-jupyter-collaboration
+jupyter-keepalive

tests/venv/postBuild/verify

@@ -1,4 +1,5 @@
 #!/bin/bash
-set -euo pipefail
-jupyter server extension list 2>&1 | grep 'jupyter_collaboration' | grep disabled
+set -xeuo pipefail
+jupyter server extension list
+jupyter server extension list 2>&1 | grep 'jupyter_keepalive' | grep disabled
 which configurable-http-proxy