Merge topic 'fix-third-party-cleanup'

e08424da

 ThirdParty: remove empty directories as well
Acked-by: Kitware Robot <kwrobot@kitware.com>
Reviewed-by: Brad King <brad.king@kitware.com>
Merge-request: !1163

ThirdParty/update-common.sh

@@ -85,6 +85,7 @@ if [ -n "$basehash" ]; then
     # Clear out the working tree
     pushd "$extractdir"
     git ls-files | xargs rm -v
+    find . -type d -empty -delete
     popd
 else
     # Create a repo to hold this package's history