Merge branch 'http-EVHTTP_CON_READ_ON_WRITE_ERROR-fixes-v2' * http-EVHTTP_CON_READ_ON_WRITE_ERROR-fixes-v2: http: try to read existing data in buffer under EVHTTP_CON_READ_ON_WRITE_ERROR test: add logging for http/read_on_write_error and rearrange code http: do not call deferred readcb if readcb is not set Refs: #749