pw_watch: Properly handle deleted directories
pw_watch: Properly handle deleted directories

Have git_ignored find the Git repo a deleted directory would have been
in, and ask that repo if the path was ignored.

Change-Id: If1db0ab6900a334336705dbcbd437335e3387b31
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/42262
Pigweed-Auto-Submit: Wyatt Hepler <cca3bedb37979eacd157a9bceb473582df8aea1e@google.com>
Commit-Queue: Auto-Submit <14637eda5603879df170705285bf30f5996692f0@pigweed.google.com.iam.gserviceaccount.com>
Reviewed-by: Keir Mierle <69344103cc60b36d6e1fbdc31ce6504b2286c646@google.com>

google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed,google/pigweed