Add /prefetto/protos to DupFileTest exclusion

These files are included in both CTS and MTS test suites, and need to be
ignored.

Bug: 150954228
Test: make cts && cts-tradefed run cts-unit-tests
Change-Id: I3ff3a52c798f7089c3f8497b73eb7f24c1db3aa2
1 file changed
tree: 43e5e4bd55fe1ab96a534d357c9aabb4c527ed63
  1. build/
  2. common/
  3. tools/
  4. OWNERS
  5. PREUPLOAD.cfg
  6. test_defs.sh