Print something if recipe not enable for architecture

scripts/check_exists.py

@@ -55,7 +55,9 @@ def main():
     if check_on_channel(sys.argv[3], parsed['package']['name'],
         parsed['package']['version'], parsed['build']['number']):
       sys.exit(0)
-  # else, there is no such package for the current platform
+  else:
+    print('Recipe %s is not enabled for the current architecture' % sys.argv[2])
+
   sys.exit(1)