Remove IP rule priority definition from test

Test should refer to IP rule priorities defined in RouteController.h,
rather than having duplicated local definition. In this way, there is no
need to modify the test when we renumber IP rule priorities in header
file.

Bug: 178688266
Tests: cd system/netd; atest
Change-Id: Idf9cfd36d5068911d8607fbf70d148f208c280ae
1 file changed