start-vnc: work around vnc client compatibility issue

start-vnc

@@ -246,7 +246,7 @@ ${sbatch_resources}
 #SBATCH --parsable
 #SBATCH --dkrzepilog=0
 cd \${HOME}
-/opt/TurboVNC/bin/vncserver -fg -geometry "${SVNC_GEOMETRY}" -localhost
+/opt/TurboVNC/bin/vncserver -fg -geometry "${SVNC_GEOMETRY}" -localhost -securitytypes none
 EOF
 }