Remove external/markdown from manifest

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Test: TreeHugger
Change-Id: If1be66f30980516b23f30b20df57b0642ce72a9a
1 file changed
tree: 2b262f526bf2eb3d9fa56e0e0a6ce68c50426101
  1. default.xml
  2. GLOBAL-PREUPLOAD.cfg
  3. OWNERS