Bug 1384419 - Remove libdmg entries from tooltool manifests. r=gps

This leaves one for l10n for now.

--HG--
extra : rebase_source : c2674d225aaa4cc09be20af25d913941f0337437

browser/config/tooltool-manifests/macosx64/cross-releng.manifest

@@ -23,15 +23,6 @@
     "unpack": true,
     "filename": "MacOSX10.7.sdk.tar.bz2"
   },
-  {
-    "version": "https://github.com/mozilla/libdmg-hfsplus rev ba04b00435a0853f1499d751617177828ee8ec00",
-    "size": 57060,
-    "visibility": "public",
-    "digest": "0c96f0d3ace71c4110abec6f7ead013600b0a73c89465d840276090d849279e555d977fb2aa6bbabb7891d7191fc8cc8a4e8242be888114be52346b77a512fcc",
-    "algorithm": "sha512",
-    "unpack": true,
-    "filename": "dmg.tar.xz"
-  },
   {
     "version": "rustc 1.19.0 (0ade33941 2017-07-17) repack",
     "size": 155690216,