autocreate/usb: check for symlinks, change DevIo message


git-svn-id: svn://svn.code.sf.net/p/fhem/code@4876 2b470e98-0d58-463d-a4d8-8e2adae1ed80
git-svn-id: svn://svn.code.sf.net/p/fhem/code@4877 2b470e98-0d58-463d-a4d8-8e2adae1ed80