libgcrypt: upgrade dev-libs/libgcrypt to version 1.8.8

BUG=chromium:1292842
TEST=Built and deployed to asurada and ocotpus. CQ Passes.

Change-Id: If7b694d8d49c894b0064095704cfd6c881fb5244
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/3358445
Reviewed-by: Stuart Langley <slangley@chromium.org>
Tested-by: Tom Shafron <shafron@google.com>
Commit-Queue: Tom Shafron <shafron@google.com>
3 files changed