We check for the existence of both leader and follower index, then properly
report to the caller. However, we do not return after reporting failure. This
causes the caller receive exception twice: IllegalArgumentException then
NullPointerException. This commit makes sure to stop the action after reporting
failure.
This commit enables the run task for ccr by specifying that the ccr
project not be evaluated until after core is evaluated. This is
important since ccr is alphabetically before core and thus Gradle
evaluates it first.
Relates #3665