Renamed the org.apache.logging.log4j.core.appender.db.nosql.mongo package to org.apache.logging.log4j.core.appender.db.nosql.mongodb.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1565900 13f79535-47bb-0310-9956-ffa450edef68