cleanup manual sigpipe handling in query.rs

[clux]

➜ media-engine git:(coverity) ✗ lal query media-engine | head -n 1
10
thread '

' panicked at 'failed printing to stdout: Broken pipe (os error 32)', ../src/libstd/io/stdio.rs:617
note: Run with RUST_BACKTRACE=1 for a backtrace.
doesn't like pipes

Fixed it locally by emulating the language's fix locally in query.rs. Basically, if we fail to flush, stop writing. Don't think it's needed anywhere else, but the fix is needed in the language really rather than everywhere else. Hopefully the comment will remind me to take it out.