Use PlatformSdkVersion from Make

This doesn't need to be hardcoded, and should be updated anyways.

Change-Id: Ie28d0d7655e8db3c02d110ae578a763a69b73f92
diff --git a/android/variable.go b/android/variable.go
index a2313d5..b0639ae 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -115,7 +115,7 @@
 
 func (v *productVariables) SetDefaultConfig() {
 	*v = productVariables{
-		Platform_sdk_version:       intPtr(22),
+		Platform_sdk_version:       intPtr(23),
 		HostArch:                   stringPtr("x86_64"),
 		HostSecondaryArch:          stringPtr("x86"),
 		DeviceName:                 stringPtr("flounder"),