kiji-rest: REST-147. Update the startup script to write to the correct logs dir.

Ensure that the startup script writes to the correct log directory and that the
logs directory exists on startup.

Review: https://review.kiji.org/r/2031/
Reviewer: shashir
commit: https://github.com/kijiproject/kiji-rest/commit/170b75895dcc14b5efea440ea19d4c629d8f5689