HDFS-6716. Update usage of KeyProviderCryptoExtension APIs on NameNode. (wang)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/fs-encryption@1612438 13f79535-47bb-0310-9956-ffa450edef68
HDFS-6718. Remove EncryptionZoneManager lock. (wang)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/fs-encryption@1612439 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-10870. Failed to load OpenSSL cipher error logs on systems with old openssl versions (cmccabe)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/fs-encryption@1612440 13f79535-47bb-0310-9956-ffa450edef68