B OpenNebula/one#6757: Add workaround instructions

Signed-off-by: Victor Hansson <[email protected]>

Author: vichansson

source/intro_release_notes/release_notes/known_issues.rst

@@ -25,6 +25,8 @@ Sunstone
 
 - The current configuration for both Sunstone and One-Provision contain a mismatch in the `keep_me_logged` configuration option. This issue has been fixed but the new configuration files need to be downloaded in order for this fix to take effect, refer to :ref:`the following section <fireedge_install_configuration>` for instructions on how to do this.
 
+- The `Update VM Configuration` dialog contains a bug which will result in a blank screen if one tries to update the configuration of a virtual machine with less than 2 total disks attached. The quickest workaround for this is to attach another minimal disk to the VM.
+
 Install Linux Graphical Desktop on KVM Virtual Machines
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