fixed in trunk r74426.  socket.socket.sendall() and all
socket._fileobject methods (read/readline/write/flush) now properly
handle EINTR internally.

sendall will allow a python signal handler to raise an exception
aborting it in unknown state, otherwise it handles EINTR as it should
and continues sending.

I'm leaving this issue open until it is merged into py3k and considered
for 2.6 and/or 3.1 release backporting.