RFR [9] 8078528: clean out tidy warnings from security.auth

[alexander stepanov]

Hello,

Could you please review the following fix
http://cr.openjdk.java.net/~avstepan/8078528/webrev.00/

for
https://bugs.openjdk.java.net/browse/JDK-8078528

Just some HTML markup cleanup for docs.

Thanks,
Alexander