Based on qemu changes made in commits ae523427 and 659ded58.

* src/lxc/lxc_driver.c (lxcSetSchedulerParametersFlags)
(lxcGetSchedulerParametersFlags, lxcDomainSetBlkioParameters)
(lxcDomainGetBlkioParameters): Use helpers.
(lxcDomainSetBlkioParameters): Allow setting live and config at
once.