Merge branch 'ls/filter-process-delayed' into jt/subprocess-handshake

* ls/filter-process-delayed: convert: add "status=delayed" to filter process protocol convert: refactor capabilities negotiation convert: move multiple file filter error handling to separate function convert: put the flags field before the flag itself for consistent style t0021: write "OUT <size>" only on success t0021: make debug log file name configurable t0021: keep filter log files on comparison