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.
adding base
abort: cannot delete applied patch c
Now at: b
a
b
a
b
series
status
Now at: a
a
b
series
status
1 New patch: a
0 base
abort: patch e not at base
f
4 New patch: f
3 New patch: e
2 New patch: d
1 New patch: a
0 base