This function has become obsolete since we've removed file-based OTA
support (it was needed by 'delete_recursive' edify function earlier).
Test: mmma -j bootable/recovery
Test: Code search shows no active user of the function.
Change-Id: If6faaa759d4c849b79acba4e6adb82baadc89f7a
Clean up the duplicated codes that handle the zip files in
bootable/recovery; and rename the library of the remaining
utility functions to libotautil.
Test: Update package installed successfully on angler.
Bug: 19472796
Change-Id: Iea8962fcf3004473cb0322b6bb3a9ea3ca7f679e