Update weaveworks/common to d442d08d89b51712ca61de3f7c14e2e218a739d7

Changes:
- Default diff-printer to hide details (#103) - da4c3ff
- Improve logging of http errors (#115) - f5a1710
- Update httpgrpc to match cortexproject/cortex#910 (#117) - 80ff076
- Expose the HTTP server from the server struct. (#118) - 1a7a6b3
- Add HTTP tracing middleware (#119) - d442d08

Author: Marcus Cobden