Add missing include. Clang build fix.

Change-Id: I74bed4f27e34c6bbf904058c14e124d8f5d35d82
diff --git a/gatekeeperd/tests/gatekeeper_test.cpp b/gatekeeperd/tests/gatekeeper_test.cpp
index 15b2b69..c504f92 100644
--- a/gatekeeperd/tests/gatekeeper_test.cpp
+++ b/gatekeeperd/tests/gatekeeper_test.cpp
@@ -14,9 +14,11 @@
  * limitations under the License.
  */
 
+#include <arpa/inet.h>
+#include <iostream>
+
 #include <gtest/gtest.h>
 #include <UniquePtr.h>
-#include <iostream>
 
 #include <hardware/hw_auth_token.h>