Configuring cpufreq service on VMs/IaaS causes an error because it doesn't supported cpufreq.
To prevent causing error, skip whole configuration when the driver not loaded.
Fixes #2051
Signed-off-by: Takuya ASADA <syuu@scylladb.com>
Message-Id: <1498809504-27029-1-git-send-email-syuu@scylladb.com>
(cherry picked from commit 1c35549932)