Check for missing client-side service config
Check for missing client-side service config

This patch fixes #769 by asserting that an attempt to create a new
libStorage client must occur concurrently alongside a configured
"libstorage.service" property.

Note: this patch must be revisited should REX-Ray ever allow for access
of the libStorage API above the level of a single service. For example,
requesting volumes for all configured services.

thecodeteam/rexray,oppodeldoc/rexray,akutz/rexray,oppodeldoc/rexray,codedellemc/rexray,thecodeteam/rexray,codedellemc/rexray,emccode/rexray,akutz/rexray,akutz/rexray,akutz/rexray,akutz/rexray,codedellemc/rexray,cduchesne/rexray,cduchesne/rexray,cduchesne/rexray,codedellemc/rexray,oppodeldoc/rexray,thecodeteam/rexray,cduchesne/rexray,oppodeldoc/rexray,akutz/rexray,emccode/rexray,oppodeldoc/rexray,oppodeldoc/rexray,cduchesne/rexray,codedellemc/rexray,emccode/rexray,thecodeteam/rexray,codedellemc/rexray,emccode/rexray,thecodeteam/rexray,thecodeteam/rexray,cduchesne/rexray