* Initial work on write concern support, set for the lifetime of the session
* Add base64 encoded value support, include docs and tests
* Handle error from json.Unmarshal, fix test and docs
* Remove writeConcern struct, move JSON unmarshal to Initialize
* Return error on empty mapping of write_concern into mgo.Safe struct
* Mention api_addr on VaultPluginTLSProvider logs, update docs
* Clarify message and mention automatic api_address detection
* Change error message to use api_addr
* Change error messages to use api_addr
Removed a trailing white space from which caused `Error loading data: Invalid key/value pair ' ': format must be key=value` if copying the example
```
vault write auth/kubernetes/role/demo \
bound_service_account_names=vault-auth \
bound_service_account_namespaces=default \
policies=default \
ttl=1h
```
* Move location of quit channel closing in exp manager
If it happens after stopping timers any timers firing before all timers
are stopped will still run the revocation function. With plugin
auto-crash-recovery this could end up instantiating a plugin that could
then try to unwrap a token from a nil token store.
This also plumbs in core so that we can grab a read lock during the
operation and check standby/sealed status before running it (after
grabbing the lock).
* Use context instead of checking core values directly
* Use official Go context in a few key places
* database/mysql: Allow the creation statement to use commands that are not yet supported by the prepare statement protocol
* Remove unnecessary else block
vault 0.9.0 deprecated the term `rules` in favor of the
term `policy` in several of the /sys/policy APIs.
The expected return state of 200 SUCCESS_NO_DATA only happens
if the `policy` term is used. A response including the
deprecation notice and a 204 SUCCESS_WITH_DATA status code
is returned when `rules` is applied.
