Make Reporter#print_incremental_result private

It's internally used but should not be exposed.

Change-Id: If185945292e3350ea9693d0fc05fa0a39663b4b1
Reviewed-on: https://gerrit.causes.com/22653
Tested-by: Aiden Scandella <aiden@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>
Add back missing hook registration

Was moved in 8ad3ecbae but I forgot to commit the changes to this file.

Change-Id: Ibe5c4a8a772488e11386754b83b90b9e75869bb0
Reviewed-on: https://gerrit.causes.com/22654
Tested-by: Aiden Scandella <aiden@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>