git: openjdk/skara: Make webrev reject positional arguments

[duke]

Changeset: e8e2f0ea
Author:    Leo Korinth <lkorinth at openjdk.org>
Committer: Erik Helin <ehelin at openjdk.org>
Date:      2019-08-26 09:56:45 +0000
URL:       https://github.com/openjdk/skara/commit/e8e2f0ea

Make webrev reject positional arguments

Reviewed-by: ehelin

! cli/resources/man/man1/git-webrev.1
! cli/src/main/java/org/openjdk/skara/cli/GitWebrev.java