add sync step in in test_term_thread
add sync step in in test_term_thread

Avoids issues caused when term fires during socket creation,
which segfaults on some buggy dev versions of libzmq-master.

But more importantly, this ensures that we are actually testing the code
we intend to - ctx.term() during blocking socket.recv().

Mustard-Systems-Ltd/pyzmq,caidongyun/pyzmq,yyt030/pyzmq,dash-dash/pyzmq,Mustard-Systems-Ltd/pyzmq,swn1/pyzmq,yyt030/pyzmq,caidongyun/pyzmq,ArvinPan/pyzmq,ArvinPan/pyzmq,swn1/pyzmq,swn1/pyzmq,Mustard-Systems-Ltd/pyzmq,ArvinPan/pyzmq,caidongyun/pyzmq,yyt030/pyzmq,dash-dash/pyzmq,dash-dash/pyzmq