mq: add qdelete --forget option
This removes an applied patch from the series and status files without
popping it. It is useful when an mq patch has been applied upstream.
#!/bin/shhg initmkfifo phg serve --stdio < p &P=$!(echo lock; echo addchangegroup; sleep 5) > p &Q=$!sleep 3kill -HUP $Pwaitls .hg