lplupdate: fixed checking for dead links

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@40283 4005530d-fff6-0310-9dd1-cebe43e6787f
lpl: update

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@40284 4005530d-fff6-0310-9dd1-cebe43e6787f
lplupdate: better message

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@40285 4005530d-fff6-0310-9dd1-cebe43e6787f