Cloning to el8 for bugfix parity.

+++ This bug was initially created as a clone of Bug #2225471 +++

Description of problem:

389-ds-base-2.3.4-2.el9 and 2.3.4-3.el9 both FTBFS with rust-1.71.0.

error: using `.borrow()` on a double reference, which returns `&concread::cowcell::CowCellReadTxn<CacheStats>` instead of borrowing the inner t
ype
  --> librslapd/src/cache.rs:60:28
   |
60 |     let stats = stat_rguard.borrow();
   |                            ^^^^^^^^^
   |
note: the lint level is defined here
  --> librslapd/src/lib.rs:1:9
   |
1  | #![deny(warnings)]
   |         ^^^^^^^^
   = note: `#[deny(suspicious_double_ref_op)]` implied by `#[deny(warnings)]`
error: could not compile `librslapd` (lib) due to previous error

This is rust issue https://github.com/rust-lang/rust/issues/112489

--- Additional comment from Josh Stone on 2023-07-25 08:55:48 PDT ---

I do not recommend deny(warnings) in production builds, since we rebase frequently and there may always be new warnings -- whether or not they are false positives.

Still, I can see about backporting the upstream fix for this.