make set_target_release_and_old_repo the default behavior

Previously, we had `set_target_release` and
`set_target_release_and_old_repo` for reconfigurator-cli because
there were concerns about the behavior of the system if the
old repo was set during the middle of an update. This has
since been fixed and the behavior of `set_target_release_and_old_repo`
is what we should use everywhere

Author: labbott

nexus/reconfigurator/planning/src/system.rs

@@ -869,33 +869,6 @@ impl SystemDescription {
     pub fn set_target_release(
         &mut self,
         description: TargetReleaseDescription,
-    ) -> &mut Self {
-        // Create a new TufRepoPolicy by bumping the generation.
-        let new_repo = TufRepoPolicy {
-            target_release_generation: self
-                .tuf_repo
-                .target_release_generation
-                .next(),
-            description,
-        };
-
-        let _old_repo = self.set_tuf_repo_inner(new_repo);
-
-        // It's tempting to consider setting old_repo to the current tuf_repo,
-        // but that requires the invariant that old_repo is always the current
-        // target release and that an update isn't currently in progress. See
-        // https://github.com/oxidecomputer/omicron/issues/8056 for some
-        // discussion.
-        //
-        // We provide a method to set the old repo explicitly with these
-        // assumptions in mind: `set_target_release_and_old_repo`.
-
-        self
-    }
-
-    pub fn set_target_release_and_old_repo(
-        &mut self,
-        description: TargetReleaseDescription,
     ) -> &mut Self {
         let new_repo = TufRepoPolicy {
             target_release_generation: self

nexus/reconfigurator/planning/tests/integration_tests/planner.rs

@@ -3158,7 +3158,7 @@ fn test_update_crucible_pantry_before_nexus() {
         artifacts,
     });
     sim.change_description("set new target release", |desc| {
-        desc.set_target_release_and_old_repo(description);
+        desc.set_target_release(description);
         Ok(())
     })
     .unwrap();
@@ -3530,7 +3530,7 @@ fn test_update_cockroach() {
         artifacts,
     });
     sim.change_description("set new target release", |desc| {
-        desc.set_target_release_and_old_repo(description);
+        desc.set_target_release(description);
         Ok(())
     })
     .unwrap();
@@ -3900,7 +3900,7 @@ fn test_update_boundary_ntp() {
         artifacts,
     });
     sim.change_description("set new target release", |desc| {
-        desc.set_target_release_and_old_repo(description);
+        desc.set_target_release(description);
         Ok(())
     })
     .unwrap();
@@ -4290,7 +4290,7 @@ fn test_update_internal_dns() {
         artifacts,
     });
     sim.change_description("set new target release", |desc| {
-        desc.set_target_release_and_old_repo(description);
+        desc.set_target_release(description);
         Ok(())
     })
     .unwrap();
@@ -4539,7 +4539,7 @@ fn test_update_all_zones() {
     });
 
     sim.change_description("set new target release", |desc| {
-        desc.set_target_release_and_old_repo(description);
+        desc.set_target_release(description);
         Ok(())
     })
     .unwrap();