Return false for known errors if log does not yet exist
Return false for known errors if log does not yet exist

Otherwise we can get a No such file or directory error.

Change-Id: Ieb8b123f0277bc0f024a5911afdf801f93f7d6dd

openstack-packages/DLRN,openstack-packages/delorean,openstack-packages/delorean,openstack-packages/DLRN