Synchronous basic.get with consumer=None is broken

[WGH-]

class SyncWrapper(object):
    def __call__(self, *args, **kwargs):
        self._read = False
        self._result = self._cb(*args, **kwargs)

The problem here is self._cb might throw FrameUnderflow exception (easy to reproduce if you have large messages), but it happens after self._read is set to False. It causes while wrapper._read to terminate early, when wrapper._result is still None, and thus message will be lost.

I'm not sure how to fix it, though.

[WGH-]

Sorry, dup of #83