C++17 is the default now.

Test: builds
Change-Id: Iba888ae7b42e2d8196ede3ab053e241ddec0d8c3
diff --git a/Android.bp b/Android.bp
index e48268b..0795b6c 100644
--- a/Android.bp
+++ b/Android.bp
@@ -17,7 +17,6 @@
 cc_defaults {
     name: "sysprop-defaults",
     srcs: ["sysprop.proto", "Common.cpp", "CodeWriter.cpp"],
-    cpp_std: "c++17",
     shared_libs: ["libprotobuf-cpp-full", "libbase", "liblog"],
 }