Fetch flaky git repos during repo sync

Since "repo sync" can handle flaky repositories, we add such
repositories to flaky_repos.xml (included by external_full.xml)
to avoid build failures.

Below is the link to an example build failure due to flaky repos:
http://sponge2/67396f73-439b-4c6f-b0b8-5fd600d23078

BUG=b/162275572
TEST=$ mkdir flake && cd flake
     $ repo init -u /path/to/manifest-internal -b master && repo sync
     $ git -C src/third_party/autotest/files/server/cros/faft/fw-testing-configs log -n 1 --pretty=format:%H
     7ed9632bfe31c5ab7f403f95194c1d8047999374
     $ git -C src/third_party/breakpad/src/third_party/lss log -n 1 --pretty=format:%H
     8048ece6c16c91acfe0d36d1d3cc0890ab6e945c

Change-Id: I5ed9ce79a3d483ca6da45705e36ca1abdab73e36
2 files changed
tree: 7ae915f6d8f77917fa1b80dda0cb2214ea60d6b6
  1. LICENSE
  2. PRESUBMIT.cfg
  3. README.md
  4. external_full.xml
  5. flaky_repos.xml
README.md

Manifests used to checkout COS source

Usage: repo init -u https://cos.googlesource.com/cos/manifest.git && repo sync.