Resilliency changes/fixes, and clear timers fix

- Fixes a bug introduced in 7f502e81c71db748c636795b86b961cb048bfdfc
  that failed to clear timer counters when metrics where reported via
  the plain graphite protocol.
- Makes sure eventlet timeouts during reporting to graphite are actually
  caught, retried, and that the socket is cleaned up.
- wrap decode_recv and stats flush in bare excepts to let both
  continue on incase of unexpected errors that didn't inherit from
  Exception.

should help trackdown or fix issue #6