Fix list_url for fish shell (#2022)

var/spack/repos/builtin/packages/fish/package.py

@@ -32,8 +32,7 @@ class Fish(Package):
 
     homepage = "http://fishshell.com/"
     url      = "http://fishshell.com/files/2.2.0/fish-2.2.0.tar.gz"
-    list_url = "http://fishshell.com/files/"
-    list_depth = 2
+    list_url = "http://fishshell.com/"
 
     version('2.2.0', 'a76339fd14ce2ec229283c53e805faac48c3e99d9e3ede9d82c0554acfc7b77a')