quiet down more third-party warnings in poppler and jsoncpp

BUG=
R=djsollen@google.com

Author: mtklein@google.com

Review URL: https://codereview.chromium.org/25319002

git-svn-id: http://skia.googlecode.com/svn/trunk@11530 2bbb7eff-a529-9590-31e7-b0007b416f81
2 files changed