Symlink is a filebased OTA feature, and the corresponding updater
function has been removed in
https://android-review.googlesource.com/#/c/350357/.
Also the only place where we call "package_extract_dir()" is to unpack
some bootloader dir in vendor's code. We plan to remove it also in a
separate bug.
Bug: 31917448
Test: mma
Change-Id: I3986d60958e64e0d5d8fa5f5bd508c579fb7fa2c
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
