Revert "BUG-7446: pull in guava-21"
Revert "BUG-7446: pull in guava-21"

This reverts commit 75b18eff1ab6fcd22c47b837798653668bd797db.

Change-Id: I29a007f8874b480ecc55b1b4605e28f2f86b9fb9
Signed-off-by: Robert Varga <b8bd3df785fdc0ff42dd1710c5d91998513c57ef@cisco.com>

opendaylight/yangtools,opendaylight/yangtools