The 'touch' command uses the system default timezone if none is
supplied. This makes zip files dependent on the timezone of the
generating machine.
Zip by default stores extended attributes (eg. ctime, atime) on Unix
systems. These can be further sources of non-determinism, so switch it
off with --no-extra
Change-Id: I7e102be7368ef339cbaf47524b90688c32a09238