eliminate duplicate line

Somehow net_domain(su) showed up twice in internal master.
Delete the duplicate line.

Change-Id: I15c102850946c30c2322d6d4edcf59407d430531

su.te

@@ -21,9 +21,6 @@ userdebug_or_eng(`
   allow su su_tmpfs:file execute;
   allow su debuggerd_prop:property_service set;
 
-  # Make su a net domain.
-  net_domain(su)
-
   # su is also permissive to permit setenforce.
   permissive su;