Small fixes.
Small fixes.

Enforce --bot when --url is used.
Add a warning when --email is not defined.
Set a default --name on rietveld patches.
Set return value.

TEST=not much
BUG=when using --url and not --bot, an exception was thrown

Review URL: http://codereview.chromium.org/348044

git-svn-id: bd64dd6fa6f3f0ed0c0666d1018379882b742947@30848 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

svn2github/chromium-depot-tools,svn2github/chromium-depot-tools,svn2github/chromium-depot-tools