RFR: XXS JDK-8195805: Doclet incorrectly updates all attributes in <a> tags when relocating links

[Jonathan Gibbons]

Please review a small localized point fix for an error when updating 
relative links in doc comments.

The problem is that `name` or `id` attributes may be updated (and should 
not be) when updating links for use in a different context.

There are other more systemic design problems in the surrounding code 
that will eventually warrant attention, but this is for a specific 
fixable error.

JBS: https://bugs.openjdk.java.net/browse/JDK-8195805
Webrev: http://cr.openjdk.java.net/~jjg/8195805/webrev.00/

-- Jon