Add note about munge in the service file to RELEASE_NOTES.

RELEASE_NOTES

@@ -29,6 +29,9 @@ of Slurm will result in loss of state information.
 If using SPANK plugins that use the Slurm APIs, they should be recompiled when
 upgrading Slurm to a new major release.
 
+NOTE: If you are not using Munge, but are using the "service" scripts to
+      start Slurm daemons, then you will need to remove this check from the
+      etc/slurm*service scripts.
 
 HIGHLIGHTS
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