Modifications to query string in beforeRequest not working since 1.6.2

[rhargreaves]

I have some code which manipulates the requestParam.url variable in a beforeRequest function. I could successfully add a query string to the URL in version 1.6.2, but since then it seems it's not possible to add a query string, either via the requestParam.url variable or requestParam.qs.

I can see via Wireshark that only the original query strings specified in the test YAML file are present.