Rely on the new plugin to do all proto generation. No need of an
external protoc setup anymore. Mvn will do it all for you.
Updated all READMEs appropriately.
Signed-off-by: Michael Stack <stack@apache.org>
This patch changes poms to use protobuf-maven-plugin instaed of
hadoop-maven-plugins generating protos. Adds a few missing READMEs too
as well as purge of unused protos turned up by the new plugin.
