Auto merge of #101203 - fortanix:raoul/remove_rls_from_git_submodule_update, r=jyn514

Avoid bootstrap from updating rls submodule

Our CI performing tests of the `x86_64-fortanix-unknown-sgx` failed with:
```
21:00:53 + ./configure --enable-lld --disable-rpath --set llvm.ninja=false --set rust.verbose-tests=true
21:00:53 + ./x.py test --stage=1 --target=x86_64-fortanix-unknown-sgx library/std --host= --no-doc --exclude src/tools/linkchecker
21:00:53 Building rustbuild
21:00:53     Finished dev [unoptimized] target(s) in 0.11s
21:00:53 Updating submodule src/tools/rls
21:00:54 Building stage0 std artifacts (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
21:00:54     Updating crates.io index
21:00:55     Updating git repository `[https://github.com/rust-lang/cargo`](https://github.com/rust-lang/cargo%60)
...
21:00:55     Updating git repository `[https://github.com/rust-lang/rust-clippy`](https://github.com/rust-lang/rust-clippy%60)
21:00:56     Updating git repository `[https://github.com/rust-lang/rustfmt`](https://github.com/rust-lang/rustfmt%60)
21:00:56 error: failed to select a version for `libgit2-sys`.
21:00:56     ... required by package `cargo v0.65.0 (https://github.com/rust-lang/cargo?rev=5514f1e0e1b3650ed8a78306198e90b66b292693#5514f1e0)`
21:00:56     ... which satisfies git dependency `cargo` of package `rls v1.41.0 (/home/jenkins/workspace/rust-sgx-ci/rust/src/tools/rls)`
21:00:56 versions that meet the requirements `^0.13.2` are: 0.13.4+1.4.2, 0.13.3+1.4.2, 0.13.2+1.4.2
21:00:56
21:00:56 the package `libgit2-sys` links to the native library `git2`, but it conflicts with a previous package which links to `git2` as well:
21:00:56 package `libgit2-sys v0.14.0+1.5.0`
21:00:56     ... which satisfies dependency `libgit2-sys = "^0.14.0"` of package `cargo v0.66.0 (/home/jenkins/workspace/rust-sgx-ci/rust/src/tools/cargo)`
21:00:56 Only one package in the dependency graph may specify the same links value. This helps ensure that only one copy of a native library is linked in the final binary. Try to adjust your dependencies so that only one package uses the links ='libgit2-sys' value. For more information, see https://doc.rust-lang.org/cargo/reference/resolver.html#links.
21:00:56
21:00:56 failed to select a version for `libgit2-sys` which could resolve this conflict
```
This is related to the version bump of `libgit2-sys` in #11004, but the root cause is the RLS is sunset (#100863). When the bootstrapper manages the git submodules, the wrong repo commit is checked out. This PR removes rls from the list of rust submodules.

Author: bors

src/bootstrap/lib.rs

@@ -534,7 +534,6 @@ impl Build {
         let rust_submodules = [
             "src/tools/rust-installer",
             "src/tools/cargo",
-            "src/tools/rls",
             "src/tools/miri",
             "library/backtrace",
             "library/stdarch",