Code review comment for lp://staging/~ev/daisy/core-storage-providers

Fixed jjo's comments:

#1 didn't require a test change, since the code functioned correctly. The correct path was written to, but we were using the path as part of the key on Rabbit. This was inconsistent with the other providers, so I changed it to fetch the path from the provider information rather than splitting it off the Rabbit message.

#2 is fixed in r243, 244, and 245.

#3 was fixed by merging lp:~ev/daisy/hardcoded_localhost into lp:daisy.