Detect overrides of @Provides method and add an error for each one.

Overriding an @Provides method is fairly rare and can be very confusing (e.g. a covariant override).  This will not be backwards compatible for open source users.

See: https://groups.google.com/d/msg/google-guice/bRo5SvmzpdI/_uIfF3yUy9gJ for the public discussion
-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=70120926
2 files changed