Return from connection_exit_connect() if we failed to create CONNECTED payload
882b389668067a29bb539d0f5bd5cb2f83b93012 forgets to return from connection_exit_connect() if connected_cell_format_payload() fails:
https://gitweb.torproject.org/tor.git/blob/HEAD:/src/or/connection_edge.c#l2613
I'm not too familiar with the high-level logic of this code, but this looks buggy.
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