rust: disable incremental build for release build

so that the release build is reproducible. a reproduciable helps
developers to perform postmortem debugging.

Fixes #19225
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>

Closes scylladb/scylladb#19374

rust/Cargo.toml

@@ -34,6 +34,7 @@ incremental = false
 [profile.rust-release]
 inherits = "release"
 debug = true
+incremental = false
 
 [profile.rust-coverage]
 inherits = "dev"