Combine cleanupBuild and deleteTmpDir

It's hard to tell if I changed any behavior, but if I did, I think I
made it better, because now we explicitly move stuff out of the chroot
(if we were going to) before trying to delete the chroot.

src/libstore/build/derivation-building-goal.cc

@@ -66,7 +66,7 @@ DerivationBuildingGoal::~DerivationBuildingGoal()
             ignoreExceptionInDestructor();
         }
         try {
-            builder->deleteTmpDir(false);
+            builder->cleanupBuild(false);
         } catch (...) {
             ignoreExceptionInDestructor();
         }