`rb_git_remote_ls` also has to call `git_remote_set_callbacks`.
`rb_git_remote_ls` also has to call `git_remote_set_callbacks`.

This is to ensure that previously set callbacks get cleared correctly.

libgit2/rugged,tpickett66/rugged,saraid/rugged,libgit2/rugged,Acidburn0zzz/rugged,libgit2/rugged,Acidburn0zzz/rugged,tpickett66/rugged,Acidburn0zzz/rugged,saraid/rugged,saraid/rugged,tpickett66/rugged