Don't specify sdk_version for stubs

The default specifies sdk_version correctly, so use
the inherited value to make it easier to make global
changes.

Bug: 144149403
Test: m
Change-Id: Ibc2a1af60f10dd5d270e502011a70e20e7ed934a
Merged-In: Ibc2a1af60f10dd5d270e502011a70e20e7ed934a

apex/sdkextensions/framework/Android.bp

@@ -48,7 +48,6 @@ stubs_defaults {
     name: "framework-sdkextensions-stubs-defaults",
     srcs: [ ":framework-sdkextensions-sources" ],
     libs: [ "framework-annotations-lib" ],
-    sdk_version: "system_current",
 }
 
 droidstubs {