jni - dynamically link C++ - saves 43 kB

Since we already ship libc++ in the apex anyway...

Before in /apex/com.android.tethering/lib:
  -rw-r--r-- 1 system system  64560 1969-12-31 16:00 libandroid_net_connectivity_com_android_net_module_util_jni.so
After:
  -rw-r--r-- 1 system system  21460 1969-12-31 16:00 libandroid_net_connectivity_com_android_net_module_util_jni.so

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I50417e69a9a0b03d24212aa3f875bf241e0b0527
diff --git a/service/Android.bp b/service/Android.bp
index a3a2825..8d491b3 100644
--- a/service/Android.bp
+++ b/service/Android.bp
@@ -33,7 +33,6 @@
     srcs: [
         "jni/com_android_net_module_util/onload.cpp",
     ],
-    stl: "libc++_static",
     static_libs: [
         "libnet_utils_device_common_bpfjni",
     ],