Update Tor binary search path for Thunderbird/Instantbird
In an earlier patch submitted, we were using ProfD for Thunderbird/Instantbird because were distributing TorBirdy as a standalone extension.
With Tor Messenger (and for the upcoming Tor Mail bundle), this has changed and we should use CurProcD instead of ProfD for locating the Tor binary. We are currently patching tor-launcher for Tor Messenger with this change but this patch should go upstream. I have attached the patch. Thanks.