make ems disconnect less verbose

[JensWalter]

current log message

thread 'tokio-runtime-worker' panicked at 'called `Result::unwrap()` on an `Err` value: HyperError(hyper::Error(Connect, ConnectError("tcp connect error", Os { code: 111, kind: ConnectionRefused, message: "Connection refused" })))', src/scaler/mod.rs:160:51
stack backtrace:
0:     0x5651c8e80380 - std::backtrace_rs::backtrace::libunwind::trace::h34055254b57d8e79
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/../../backtrace/src/backtrace/libunwind.rs:90:5
1:     0x5651c8e80380 - std::backtrace_rs::backtrace::trace_unsynchronized::h8f1e3fbd9afff6ec
at /rustc/a178d0322ce20e33eac124758e837cbd80a6f633/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
2:     0x5651c8e80380 - std::sys_common::backtrace::_print_fmt::h3a99a796b770c360
...