Revert "roll: clang"

This reverts commit 7a9b71a.

Reason for revert: This roll has a known issue with FlatMap template params. Reverting the auto roll.

Original change's description:
> roll: clang
>
> From: git_revision:c58bc24fcf678c55b0bf522be89eff070507a005
> To: git_revision:ca260e1b119b043195158098a9afda3967c6854b
> Roller-URL: https://ci.chromium.org/b/8755188484734766849
> CQ-Do-Not-Cancel-Tryjobs: true
> Change-Id: Ic97ab8328c4ff35a75d605fd1ed002132a573510
> Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/193790
> Bot-Commit: Pigweed Roller <[email protected]>
> Commit-Queue: Pigweed Roller <[email protected]>

# Not skipping CQ checks because original CL landed > 1 day ago.

Change-Id: Ic3bf8def754e52242ba8bbbd2a31c1675313f0aa
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/193890
Reviewed-by: Prabhu Karthikeyan Rajasekaran <[email protected]>
Reviewed-by: Rob Mohr <[email protected]>
Pigweed-Auto-Submit: Prabhu Karthikeyan Rajasekaran <[email protected]>
Commit-Queue: Rob Mohr <[email protected]>
Pigweed-Auto-Submit: Rob Mohr <[email protected]>

pw_env_setup/py/pw_env_setup/cipd_setup/pigweed.json

@@ -71,7 +71,7 @@
         "windows-amd64"
       ],
       "tags": [
-        "git_revision:ca260e1b119b043195158098a9afda3967c6854b"
+        "git_revision:c58bc24fcf678c55b0bf522be89eff070507a005"
       ],
       "version_file": ".versions/clang.cipd_version"
     },