Should fix http://bugs.rosalinux.ru/show_bug.cgi?id=4329
If CPU frequency scaling is not supported (e.g. in a virtual machine),
cpupower will still be installed but its service will not be enabled.
If CPU frequency scaling is supported, cpupower will now use
- "ondemand" governor with "acpi_cpufreq" driver;
- "powersave" governor with "intel_pstate" driver.
These drivers support different sets of governors (for example,
"intel_pstate" does not support "ondemand") and therefore are
handled differently now.