We introduces the installation option "--default-restic-prune-frequency" to make restic prune frequency configuration in the previous release, but there is a bug that make the option don't take effect. This commit fixes the bug by removing the evaluation part. The restic repository controller will take care the prune frequency for the repository
Fixes#3062
Signed-off-by: Wenkai Yin(尹文开) <yinw@vmware.com>