nixUnstable: Update to 1.7pre3327_0e2ca26

Also fixes disappeared tarball.

(cherry picked from commit 8ad41b92cfd604e4f5ab487ad0f1784f1fc9773c)
Signed-off-by: Shea Levy <shea@shealevy.com>

Conflicts:
	pkgs/tools/package-management/nix/unstable.nix