bolt k/v pairs are only valid for the life of a transaction.
This means the memory that the k/v pair is referencing may be invalid if
it is accessed outside of the transaction.
This can potentially cause a panic.
For reference: https://godoc.org/github.com/boltdb/bolt#hdr-Caveats
To fix this issue, unmarshal the stored data into volume meta before
closing the transaction.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit 4876a9047e)
Signed-off-by: Victor Vieux <vieux@docker.com>