Remove enable_rust_boringssl

 - this flag is no longer needed, rust is now defaulted to enabled
   so no special configution is required to build this crate

Change-Id: I8234c574e893100f0b339f1d0b8058da57234706
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5341496
Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Commit-Queue: Nabil Wadih <nwadih@google.com>
Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: David Benjamin <davidben@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1274296}
NOKEYCHECK=True
GitOrigin-RevId: 7307f2069dbd72ad26e44cb01f2cbc61a9366567
1 file changed