Use zip2zip to copy zipfiles

ZipDelete() works by copying every non-deleted entry to a new zipfile.
Current implementation uses python's zipfile module to perform entry
copying, which is inefficient, as every entry must be decompressed and
then re-compressed. Instead, use zip2zip which avoid re-compression.

Improvement: deleting META/dynamic_partitions_info.txt from
raven-target_files-9465001.zip improved from 500+ seconds to 13 seconds.

Change-Id: I0548255bc29380303314763f6d81e74bf3dbb76e