obfsproxy executable no longer needed in Tor Browser
Yawning tells me that all the PT protocols in Tor Browser except fte, meek, flashproxy use obfs4proxy as their client.
Yet we still ship all the Python obfsproxy goo.
Apparently we do this for fte, which pulls it in.
But fte doesn't use the obfsproxy binary, so we can delete that after the build process and before the bundling process.