!456 add /system/usr to sandbox

Merge pull request !456 from zhanghaibo/add_usr_to_sandbox

interfaces/innerkits/sandbox/system-sandbox.json

@@ -24,6 +24,10 @@
             "src-path" : "/system/fonts",
             "sandbox-path" : "/system/fonts",
             "sandbox-flags" : [ "bind", "rec", "private" ]
+        }, {
+            "src-path" : "/system/usr",
+            "sandbox-path" : "/system/usr",
+            "sandbox-flags" : [ "bind", "rec", "private" ]
         }, {
             "src-path" : "/vendor",
             "sandbox-path" : "/vendor",