Use custom firefox path for bok-choy tests (firefox 42)

This is a backwards-compatible window for this upgrade. It will
later be replaced with using the default location (whatever's on
PATH)

scripts/generic-ci-tests.sh

@@ -158,6 +158,13 @@ case "$TEST_SUITE" in
         ;;
 
     "bok-choy")
+
+        # Back compatibility support for firefox upgrade:
+        # Copy newer firefox version to project root,
+        # set that as the path for bok-choy to use.
+        cp -R $HOME/firefox/ firefox/
+        export SELENIUM_FIREFOX_PATH=firefox/firefox
+
         case "$SHARD" in
 
             "all")