start-vnc: blurb for setting password

start-vnc

@@ -211,6 +211,7 @@ prepare_vncserver () {
     ssh_frontend "mkdir -p .startvnc"
     if ! ssh_frontend "test -s .vnc/passwd"; then
         echo "No VNC password found. Please set now."
+        echo "Do not use your LDAP password. Eight characters maximum."
         ssh_frontend "salloc -Q -n1 -pgpu -A${SVNC_ACCTCODE} -- /bin/bash -c \
                      'ssh -tt \$SLURM_JOB_NODELIST -- mkdir -p .vnc \
                      && /opt/TurboVNC/bin/vncpasswd'" "-t"