Log Message:
Update py-carbon to 0.9.12.

Changes in 0.9.12:
- Just a version bump.

Changes in 0.9.11:
- Improvements to setup.py rpm generation and basic init scripts (bmhatfield)
- Allow alternate update rate at shutdown (Daniel314)
- Add support for new fallocate() allocation method in Whisper (slackhappy)
- Improvements to noisy logging (nleskiw, drawks)
- Protect against writes outside the storage tree
- Performance fixes to rate limiting, removal of unnecessary locks (drawks)
- Alternate write strategies for carbon-cache (max size, random) (drawks)
- carbon-aggregator aware consistent-hashing for carbon-relay (slackhappy)
- Allow custom umask to be passsed to twisted at startup (egnyte)
- New options WRITE_BACK_FREQUENCY to control frequency of partially-
  aggregated output (jdanbrown)
- Improve consistent-hashing performance when replication factor is 1
  (slackhappy)
- Various code cleanups (sejeff)
- Allow a timestamp of -1 to be sent to aggregator to set to current time
  (gwillem)
- Allow log rotation to be handled by an external process (justinvenus)
- min/max aggregation methods are now supported (ishiro)
- Empty lines match everything in whitelist (gographs)
- Storage-schemas dont auto reload when they should
- Carbon-relay per-destination metrics are broken
- Regression in MAX_CREATES_PER_MINUTE where values >60 were set to 0
  (jeblair)
- Memory leak in carbon-aggregator in certain cases (lbosson)
- Python2.4 compatibility in AMQP send/receive (justinvenus)
- Cache/queue sizes are misreported (bitprophet)
- NaN values shouldn't be passed through from amqp (llaurent)