Delete all remaining callers of iptables.

Also move to binder_test.cpp some string constants that are used
only there.

Bug: 28362720
Test: bullhead builds,boots
Test: netd_{unit,integration}_test pass
Change-Id: I9eee599aafa696cbf3a1f65c3814a33ed99d65fc
diff --git a/tests/binder_test.cpp b/tests/binder_test.cpp
index 41fc8c3..b2f362e 100644
--- a/tests/binder_test.cpp
+++ b/tests/binder_test.cpp
@@ -49,6 +49,9 @@
 #include "android/net/UidRange.h"
 #include "binder/IServiceManager.h"
 
+#define IP_PATH "/system/bin/ip"
+#define IP6TABLES_PATH "/system/bin/ip6tables"
+#define IPTABLES_PATH "/system/bin/iptables"
 #define TUN_DEV "/dev/tun"
 
 using namespace android;