grep: remove useless while condition
A revised version of 35ba170c0f82 was sent to the list that fixed this
<http://markmail.org/message/jmfuiise5igcyh2m>, but the older version of
the patch was applied.
http://mercurial.selenic.com/bts/issue1089
$ hg init
$ mkdir a
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b (glob)
$ hg ci -m m a
$ mkdir a b
$ echo a > a/b
$ hg ci -Am m
adding a/b
$ hg rm a
removing a/b (glob)
$ cd b
Relative delete:
$ hg ci -m m ../a
$ cd ..