fixes a flaky test
Added default value for task version
Merge pull request #615 from mesosphere/task-version-default

Added default value for task version
Setting version to 0.7.0-RC4
Setting version to 0.7.0-SNAPSHOT
Merge pull request #614 from mesosphere/wip-fix-flaky-test

fixes a flaky test in DeploymentActorTest.scala
[reconciliation] Increase interval from 30 -> 60s.
[reconciliation] Don't kill tasks on ZK failure.