Roll back rust

The env-setup-builder-mac last worked with this Rust version. I've also
paused the rust roller.

https://ci.chromium.org/p/pigweed/builders/ci/env-setup-builder-mac?limit=200

Change-Id: I73af045252d9b2bfdcd45e3cac1e5e8b7f864458

pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json

diff --git a/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json b/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json
index 6b1c403..9b82df6 100644
--- a/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json
+++ b/pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json
@@ -79,7 +79,7 @@
     "_comment": "TODO(pwbug/69) Put rust in cipd for Windows.",
     "path": "fuchsia/rust/${os=linux,mac}-${arch=amd64}",
     "tags": [
-      "git_revision:eeaf497b2a6bc065874e3d3367b1f3023c5bb3d3"
+      "git_revision:027149919e36ce5645ca5d02d55b97ef52eb55ba"
     ]
   },
   {