try to modify ceedling lib/rakefile.rb to exit 0 if build succeeded

tests/vendor/ceedling/lib/rakefile.rb

@@ -70,5 +70,6 @@ END {
 	  @ceedling[:plugin_manager].post_build
 	  @ceedling[:plugin_manager].print_plugin_failures
 	  exit(1) if (@ceedling[:plugin_manager].plugins_failed?)
+	  exit(0)
 	end
 }