I wanted to pull commit \"3a2ceef391af73994dfeb0d8ef57ed6a52ef4238\" from branch android. I used the command:
$ git fetch origin 3a2ceef391af73994dfeb0d8ef57ed6a
I got the same error and none of these resolved it. It turned out that I hadn't pushed submodule changes from my other computer (this would give 404 error when you click on submodule folder on GitHub). So pushing submodule, committing parent and pushing that as well resolved the error.
Other solutions are git submodule update --recursive
and this.