CB: Add system property to enable/disable dup detection

If system property persist.cb.dup_detection is set to false, duplicate
detection is disabled.  If it is set to true, duplicate detection is
enabled.  If the system property does not exist, using true/enabled
as a default value.

Change-Id: If377675c46950b4a03253fa29c2d8ae1c5804544
(cherry picked from commit d39c79169dac8773281b5b5f7e6bba073e269e94)
(cherry picked from commit ad167a8ffbaa1dd84fb5266f156b29a7cdea5298)
(cherry picked from commit 0f7cac5c8005eb4bb9d7d5d0ff23ae62f5c07944)