made the test for shdict:get_stale less possible to fail.

t/043-shdict.t

@@ -1463,7 +1463,7 @@ cur value:  hello hello hello hello hello hello hello hello hello hello1
             local dogs = ngx.shared.dogs
             dogs:set("foo", 32, 0.01)
             dogs:set("blah", 33, 0.1)
-            ngx.sleep(0.01)
+            ngx.sleep(0.02)
             local val, flags, stale = dogs:get_stale("foo")
             ngx.say(val, ", ", flags, ", ", stale)
             local val, flags, stale = dogs:get_stale("blah")