Fix reusing bufferevent_openssl after fd was reseted (i.e. on new connection)

Fix reusing bufferevent_openssl after fd was reseted (i.e. on new connection)

For example if you trying to issue multiple requests over the same
evhttp_conneciton, and if connection already closed (IOW it should be
re-connected), than you will get into trouble since it will got wrong
openssl state. This patch addresses this issue by restoring state to
initial if SETFD called with -1 fd.