Ensure trailing slash on tree for cobbler-utils

[sfloess]

Should be: cobbler-exec distro edit --name="${DISTRO_NAME}" --in-place --ksmeta="tree=http://@@server@@/cblr/links/${DISTRO_NAME}/" with a trailing slash. Not cobbler-exec distro edit --name="${DISTRO_NAME}" --in-place --ksmeta="tree=http://@@server@@/cblr/links/${DISTRO_NAME}