This commit adds a check to the dynamic inventory script when parsing extra values
Allow default drives to be specified for swift

* Drives can now be specified in the global variables
* Drives specified per device will take precedence
* Set ownership on the appropriate set of drives

Fixes: #511
Allow a default mount_point to be specified

* Specify a default mount_point in global_overrides
* Can still be specified per node but not required.
* Allows this to be specified in one place only

Fixes #513
Add support for dedicated replication network

* Allow 2 servers to run (one on the replication network)
* Split out the replication configuration
* Set a specific replication_network
* Fix service names

Partial-fixes: #516
Merge pull request #512 from andymcc/swift_default_drives

Allow default drives to be specified for swift
Merge pull request #514 from andymcc/mount_point_def

Default out mount_point and drives
Merge pull request #519 from andymcc/swift_repl_setup

Add support for dedicated replication network
Merge pull request #492 from cloudnull/string-check

Additional change required for Cinder AZ options