The current code fixes the path to make it absolute when cloning, but
doesn't consider tilde expansion, so that scenario fails throwing an
exception because /home/myuser/~/my/repository doesn't exists:
$ git clone hg::~/my/repository && cd repository && git fetch
Expand the tilde when checking if the path is absolute, so that we don't
fix a path that doesn't need to be.
Signed-off-by: Antoine Pelisse <apelisse@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>