Failed qimport of patches from files should cleanup by recording successfully

imported patches in series file.

  $ echo "[extensions]" >> $HGRCPATH

  $ echo "mq=" >> $HGRCPATH

  $ hg init repo

  $ cd repo

  $ echo a > a

  $ hg ci -Am'add a'

  adding a

  $ cat >b.patch<<EOF

  > diff --git a/a b/a

  > --- a/a

  > +++ b/a

  > @@ -1,1 +1,2 @@

  >  a

  > +b

  > EOF

  $ echo

empty series

  $ hg qseries

  $ echo

qimport valid patch followed by invalid patch

  $ hg qimport b.patch fakepatch

  adding b.patch to series file

  abort: unable to read file fakepatch

  [255]

  $ echo

valid patches before fail added to series

  $ hg qseries

  b.patch