OS X: Fix Info.plist placement in a CFBundle

Fix cmOSXBundleGenerator::CreateCFBundle to place Info.plist under the
same root directory as the rest of the bundle.  Without this, Info.plist
was placed into CMAKE_BINARY_DIR, not CMAKE_CURRENT_BINARY_DIR because
the target path was not generated correctly.
Merge branch 'osx-CFBundle-info-plist' into release