ksoap2 - compile against system_30

Bug: 171330443
Test: compiles
Change-Id: Ib44d39671b82e2811cda678ca517872480077f8b
diff --git a/Android.bp b/Android.bp
index 2075b81..9f9ce89 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,5 +1,5 @@
 java_library {
     name: "ksoap2",
-    sdk_version: "system_current",
+    sdk_version: "system_30",
     srcs: ["**/*.java"],
 }