test CmdRun/Terminate: fix do ... finally

This makes the `finally` apply to the last `do` block as intended.
No real effect on the test, though.

cabal-testsuite/PackageTests/NewBuild/CmdRun/Terminate/Main.hs

@@ -6,9 +6,9 @@ import System.Exit (exitFailure)
 main = do
   mainThreadId <- myThreadId
   Signal.installHandler Signal.sigTERM (Signal.Catch $ killThread mainThreadId) Nothing
-  do
+  (do
     putStrLn "about to sleep"
     writeFile "exe.run" "up and running"
     threadDelay 10000000 -- 10s
-    putStrLn "done sleeping"
-  `finally` putStrLn "exiting"
+    putStrLn "done sleeping")
+    `finally` putStrLn "exiting"