Undo 0.6.0 .auroraversion and CHANGELOG changes to prepare for 0.6.0-RC1

Bugs closed: AURORA-711

Reviewed at https://reviews.apache.org/r/27830/
Updating CHANGELOG for 0.6.0 release.
Incrementing snapshot version to 0.6.1-SNAPSHOT.
Print out the job url after scheduling a cron job.

Bugs closed: AURORA-857

Reviewed at https://reviews.apache.org/r/27657/
Remove stracktrace redirection.

Bugs closed: AURORA-896

Reviewed at https://reviews.apache.org/r/27710/