Handle the invalid timestamp in zipfile

The month field is one based in the zipfile modification time. And
it causes an overflow converting it to struct tm. Switch to type to
signed integer to suppress the sub-overflow.

Bug: 153882979
Test: parse the problematic zipfile
Change-Id: Iaf47bcc7f83d61b18c9e7a98bb6ab3936c9257e3
Merged-In: Iaf47bcc7f83d61b18c9e7a98bb6ab3936c9257e3
(cherry picked from commit 426bf3a1)