Add missing ref to out

Author: psigen

rules/native_binary.bzl

@@ -25,7 +25,7 @@ def _impl_rule(ctx):
         out_file = ctx.attr.out
     else:
         out_file = ctx.name
-    ctx.actions.declare_file(out_file)
+    out = ctx.actions.declare_file(out_file)
 
     ctx.actions.symlink(
         target_file = ctx.executable.src,