google-breakpad: Merge with upstream breakpad r981

BUG=none
TEST=Verified the following:
1. emerge google-breadpad for x86-generic, arm-generic and amd64-generic
2. cros_run_unit_tests google-breakpad for x86-generic and amd64-generic
3. Run the following autotest tests on a Cr48:
   - logging_CrashSender
   - logging_UserCrash

Change-Id: I896843259257c3adddcade76e82d77cae87dba06