[phobos] [D-Programming-Language/phobos] bef28f: Allow TypedAllocator.Policies to actually be empty

[GitHub via phobos]

  Branch: refs/heads/master
  Home:   https://github.com/D-Programming-Language/phobos
  Commit: bef28f41f1490e3949410c168f7162d3a72a5159
      https://github.com/D-Programming-Language/phobos/commit/bef28f41f1490e3949410c168f7162d3a72a5159
  Author: Justin Whear <justin at economicmodeling.com>
  Date:   2015-10-02 (Fri, 02 Oct 2015)

  Changed paths:
    M std/experimental/allocator/typed.d

  Log Message:
  -----------
  Allow TypedAllocator.Policies to actually be empty

Fixed compile-time error when Policies was empty. Repro with
----
import std.experimental.allocator.mallocator;
import std.experimental.allocator.typed;
alias A = TypedAllocator!(Mallocator);  // slice[1..0]
----


  Commit: 158de887d3fd3393f11269eb2240f36c8b16cd61
      https://github.com/D-Programming-Language/phobos/commit/158de887d3fd3393f11269eb2240f36c8b16cd61
  Author: Brian Schott <briancschott at gmail.com>
  Date:   2015-10-15 (Thu, 15 Oct 2015)

  Changed paths:
    M std/experimental/allocator/typed.d

  Log Message:
  -----------
  Merge pull request #3685 from economicmodeling/allocator_policy_fix

Allow TypedAllocator.Policies to actually be empty


Compare: https://github.com/D-Programming-Language/phobos/compare/cfca3d6037c7...158de887d3fd