Events: fixed eventport handling in ngx_handle_read_event(). The "!rev->ready" test seems to be a typo, introduced in the original commit (719:f30b1a75fd3b). The ngx_handle_write_event() code properly tests for "rev->ready" instead. Due to this typo, read events might be unexpectedly removed during proxying after an event on the other part of the proxied connection. Catched by mail proxying tests.