Only report not using latest versions when using < latest

Rather than when /= latest. So we'll no longer report things like:

  hdevtools-0.1.0.6 (latest: 0.1.0.5) (new package)

We don't need to tell people they're not using the latest version when
they're actually using a later version than the one available (e.g.
it's installed locally and not available from the remote server).

Reported by bennofs

cabal-install/Distribution/Client/Install.hs

@@ -578,7 +578,7 @@ printPlan dryRun verbosity plan sourcePkgDb = case plan of
     showLatest :: ConfiguredPackage -> String
     showLatest pkg = case mLatestVersion of
         Just latestVersion ->
-            if pkgVersion /= latestVersion
+            if pkgVersion < latestVersion
             then (" (latest: " ++ display latestVersion ++ ")")
             else ""
         Nothing -> ""