Disconnecting from network during sync can panic zingo-cli

[AloeareV]

{
  "result": "failure",
  "latest_block": 2154100,
  "total_blocks_synced": 0
}
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: UnexpectedCharacter { ch: 'E', line: 1, column: 1 }', zingocli/src/lib.rs:144:41
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace