A fix for @ezyang's fix for #2502.

Instead of:
C:\Users\Ganesh\AppData\Local\Temp\data-default-instances-old-locale-0.0.1-11924\data-default-instances-old-locale-0.0.1
(which was the case before @ezyang's patch)
we now get:
C:\Users\Ganesh\AppData\Local\Temp\cabal-tmp-11924\data-default-instances-old-locale-0.0.1

Fixes #2658.

cabal-install/Distribution/Client/Install.hs

@@ -1267,10 +1267,10 @@ installLocalTarballPackage
 installLocalTarballPackage verbosity jobLimit pkgid
                            tarballPath distPref installPkg = do
   tmp <- getTemporaryDirectory
-  withTempDirectory verbosity tmp (display pkgid) $ \tmpDirPath ->
+  withTempDirectory verbosity tmp "cabal-tmp" $ \tmpDirPath ->
     onFailure UnpackFailed $ do
-      let relUnpackedPath = "."
-          absUnpackedPath = tmpDirPath
+      let relUnpackedPath = display pkgid
+          absUnpackedPath = tmpDirPath </> relUnpackedPath
           descFilePath = absUnpackedPath
                      </> display (packageName pkgid) <.> "cabal"
       withJobLimit jobLimit $ do