Revert: "archive/zip: handle mtime in NTFS/UNIX/ExtendedTS extra fields"
This change reverts the following CLs:
CL/18274: handle mtime in NTFS/UNIX/ExtendedTS extra fields
CL/30811: only use Extended Timestamp on non-zero MS-DOS timestamps
We are reverting support for extended timestamps since the support was not
not complete. CL/18274 added full support for reading extended timestamp fields
and minimal support for writing them. CL/18274 is incomplete because it made
no changes to the FileHeader struct, so timezone information was lost when
reading and/or writing.
While CL/18274 was a step in the right direction, we should provide full
support for high precision timestamps in both the reader and writer.
This will probably require that we add a new field of type time.Time.
The complete fix is too involved to add in the time remaining for Go 1.8
and will be completed in Go 1.9.