cvs-plugin part of fix for JENKINS-23234: jenkins cvs update hang when r...

ignore symlinks (when recursing) like the major cvs clients.
agree on printing and remove issue ID in messages and comments.

On the checking of symlink and catch of exception . . . 
I do think the catch is needed when checking for symlink.
I do not want to introduce a change which would break jenkins cvs for users who are working happily with projects on various different OSs. 
I'm afraid I'm not that experienced with java and the examples I found of symlink checking generally used try ... catch.
I'm not sure would this exception be rare or a more common case.