Enable all skipped tests in sock_diag_test.

All device trees that run kernel/tests from master should have
the required commits now.

Test: all_tests.sh passes on android-3.18.
Change-Id: I13962c95330e92d15df7b2b26dbbd06999af2cf8
diff --git a/net/test/sock_diag_test.py b/net/test/sock_diag_test.py
index fb1e344..1d57c34 100755
--- a/net/test/sock_diag_test.py
+++ b/net/test/sock_diag_test.py
@@ -631,7 +631,6 @@
       self.ExpectNoPacketsOn(self.netid, msg)
 
 
-@unittest.skipUnless(net_test.LINUX_VERSION >= (4, 9, 0), "does not yet exist")
 class SockDestroyUdpTest(SockDiagBaseTest):
 
   """Tests SOCK_DESTROY on UDP sockets.
@@ -755,7 +754,6 @@
     self.CheckPermissions(SOCK_STREAM)
 
 
-@unittest.skipUnless(net_test.LINUX_VERSION >= (4, 9, 0), "does not yet exist")
 class SockDiagMarkTest(tcp_test.TcpBaseTest, SockDiagBaseTest):
 
   """Tests SOCK_DIAG bytecode filters that use marks.