Exclude tor dependencies from LD_LIBRARY_PATH

In our startup script we add the TorBrowser/Tor directory to LD_LIBRARY_PATH, but we don't need to and it might cause the browser not to work (tor-browser#43326).

With tor-browser!1301, I'm setting LD_LIBRARY_PATH in the code of the browser that starts the tor daemon, but we should also remove the lines from our startup script.

@morgan says we could switch to static dependencies otherwise.