Use correct system_modules with core.current.stubs

The system_modules defn used with core.current.stubs
was core-system-modules which doesn't match. Instead,
this change uses core-current-stubs-system-modules.

Test: build
Change-Id: Ifb9e77b02bbb04c1cb39c6b9f97932c20d44d8ba
diff --git a/java/sdk.go b/java/sdk.go
index e93f8fb..506edfb 100644
--- a/java/sdk.go
+++ b/java/sdk.go
@@ -151,7 +151,7 @@
 		}
 
 		if m == "core.current.stubs" {
-			ret.systemModules = "core-system-modules"
+			ret.systemModules = "core-current-stubs-system-modules"
 		} else if m == "core.platform.api.stubs" {
 			ret.systemModules = "core-platform-api-stubs-system-modules"
 		}