Tighten auth_rw_shadow_lock permission

There are no directories labeled shadow_lock_t, and therefore is no
reason to grant dir:search on shadow_lock_t.

Signed-off-by: Antonio Enrico Russo <aerusso@aerusso.net>

Author: aerusso

policy/modules/system/authlogin.if

@@ -862,7 +862,7 @@ interface(`auth_rw_shadow_lock',`
 		type shadow_lock_t;
 	')
 
-	rw_files_pattern($1, shadow_lock_t, shadow_lock_t)
+	allow $1 shadow_lock_t:file rw_file_perms;
 ')
 
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