Remove the implicit "_" in subnames.

The NDK stub libraries need to use subname, but should use "." instead
of "_".

Test: Still builds.
Change-Id: Ib4b0303531e03968c55671ea167ab987adebd783

android/androidmk.go

@@ -146,7 +146,7 @@ func translateAndroidMkModule(ctx blueprint.SingletonContext, w io.Writer, mod b
 	}
 
 	if data.SubName != "" {
-		name += "_" + data.SubName
+		name += data.SubName
 	}
 
 	if data.Custom != nil {