git send-email -v n fails

I think send-email should understand all options of format-patch.
At least for '-v n' this fails, one has to type '--reroll-count n' as a
workaround with git version 2.13.3:

+ git send-email -v 2 --annotate --confirm=always --to-cmd=scripts/get_maintainer.pl 'HEAD^'
fatal: ambiguous argument '2': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'
format-patch -o /tmp/fVUtbB6OWI 1 HEAD^: command returned error: 128

Olaf