update sys-libs/zlib to 1.2.11

BUG=b:62214372
BUG=b:62285362
CQ-DEPEND=CL:522949
TEST=emerge zlib

Change-Id: I2b3bb0078888efc59039dc7c803e6efc24520264
Reviewed-on: https://chromium-review.googlesource.com/520704
Commit-Ready: Andrey Ulanov <andreyu@google.com>
Tested-by: Andrey Ulanov <andreyu@google.com>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
3 files changed