Made fixes for mono. [Backpatch cherry pick]

- Disable performance counters if running on mono.
- Use DefaultProtectedData if running on mono.

(cherry picked from commit 57e1c98b9a7da049f8d0e73f781acf65285f7741)
Merge branch 'release1.x' of github.com:BrandonLWhite/SignalR into release1.x