Build framework-telephony-stubs against core_current

Build framework-telephony-stubs against
core_current so that it can be linked by
framework-wifi, which will also be built
against core_current.

Bug: 140908357
Test: device boots up
Change-Id: I20bf13a100d6dfca06c4e108a837987234ec2b38
diff --git a/Android.bp b/Android.bp
index 0e3d374..1ddfbe5 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1266,7 +1266,8 @@
     aidl: {
         export_include_dirs: ["telephony/java"],
     },
-    sdk_version: "system_current",
+    sdk_version: "core_current",
+    libs: ["android_system_stubs_current"],
 }
 
 java_library {