thrift: 0.9.2 -> 0.9.3

Add Twisted as build input so that we can continue to have Python
support. (./configure disables Python support unless it finds the
'trial' program, from Twisted.) I don't know whether upstream intended
that, because it seems perfectly fine to run thrift + Python without
Twisted. (Only the TTwisted transport uses Twisted...)

Ah, Thrift use Twisted in its unit tests. Even when we pass
--enable-tests=no to ./configure :-D