GODRIVER-3470 Correct BSON unmarshaling logic for null values (#1924) [master] (#1945) [release/2.0]#1947

matthewdale merged 1 commit intorelease/2.0mongodb/mongo-go-driver:release/2.0from

cherry-pick-release/2.0-25df82ff2956607022f725f544f10261dd08796dmongodb/mongo-go-driver:cherry-pick-release/2.0-25df82ff2956607022f725f544f10261dd08796dCopy head branch name to clipboard