Fix duplicate 'META/care_map.txt' when calling add_img_to_target_files

In case the system/vendor image is updated for an A/B target file, we'll
delay the write of META/care_map.txt. Specifically, we'll run "zip -d"
to remove the old entry and then zip in the new one from tmp dir.

Bug: 62345693
Test: Run add_img_to_target_files.py on sailfish target files, and
care_map.txt is updated.

Change-Id: Id2f9997aac50c0740e6944d0d0d43d98f5fc6c29