cvs-plugin part of fix for JENKINS-23234: jenkins cvs update hang when recursive symlink in directory. ignore symlinks like the major cvs clients.
cvs-plugin part of fix for JENKINS-23234: jenkins cvs update hang when recursive symlink in directory. use logger not print to stderr
cvs-plugin part of fix for JENKINS-23234: update after review: add curlies for if, simplify and remove references to issue in log output and comments, use listener.error in case of exception when checking for symlink.
Merge pull request #31 from Gaoithe/fix-jenkins-23234_ignore_symlinks

[JENKINS-23234] Prevent infinite recursion on symlink resolution during CVS checkout