Add dummy readme in examples/src/../scala/hello for Intellij plugin integration tests.

We added capability to the pants plugin to index non target owning files e.g. deploy scripts or READMEs
here https://rbcommons.com/s/twitter/r/1338/

We added the for the plugins.
Integration tests for Intllij plugin

Testing Done:
yes.
https://github.com/pantsbuild/pants/commit/d0fc5d05e8fae14311bab4cb7e664fa23fb02a8c

Reviewed at https://rbcommons.com/s/twitter/r/1356/
Sync of https://github.com/pantsbuild/pants/commit/54b122f88fe9a15e73638316cf113da558f929c2