Correct typo in server_environment.cfg

Author: marcosbento

releng/imachination/ecflow/deploy/workspace/server_environment.cfg

@@ -183,6 +183,6 @@ ECF_TASK_THRESHOLD = 4000
 # *   - w: write permission
 # *   - x: execute permission
 # *   - o: override permission
-# *   - a: administrator permission (cannot be overridden)
+# *   - s: administrator permission (cannot be overridden)
 # **************************************************************************
 ECF_PERMISSIONS = admin:rwxo