Added volumeMountPath option for docker volume mounts
Added volumeMountPath option for docker volume mounts

This commit introduces a new configurable field for
docker.volume.mountPath to choose the default location of
mounted volumes. A path of /var/lib/rexray/volumes is still
default as a base.

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