Re #8882. Update instructions.

Code/Mantid/Build/Jenkins/notes.md

@@ -1,3 +1,3 @@
-* In order to be able to use xvnc in a matrix job, an empty executable called vncserver should be placed in the path (e.g. /usr/local/bin) on all Mac buildservers.
+* In order to be able to use xvnc in a matrix job, the "Disable Xvnc execution on this node" should be selected for all Mac nodes.
 * Machines that are set up to build Mantid should have a label of the form OS-build, where OS is one of rhel6, ubuntu-12.04, osx-10.8, windows7
 * Similarly, machines that are to be used to run the system tests should have a label of the form OS-test