MINOR: backend: Don't release SI endpoint anymore in connect_server()

Thanks to the previous patch (822decfd "BUG/MAJOR: stream-int: Release SI
endpoint on server side ASAP on retry"), it is now useless to release any
existing connection in connect_server() because it was already done in
back_handle_st_cer() if necessary.

This patch is not a CLEANUP because it may introduce some bugs in edge
cases. There is no reason to backport it for now except if it is required to
fix a bug.
1 file changed