Don't try to preserve permissions when downloading results files.
Don't try to preserve permissions when downloading results files.

Issues:
Fixes #589

Problem:
- Nightly regression jobs report errors like "cp: preserving times for
  'x': Operation not permitted" at the point where they try to download
  systest results logs.
- While not a blocker (because the job *does* run to completion and
  *does* successfully download the results files), this unexpected error
  is a nuisance because it causes the Jenkins weather report to remain
  stormy.

Analysis:
- Don't pass the -p flag when calling cp to download the results files.
- It is a known issue with cp that -p won't work if the owner of the
  source file doesn't match the owner of the destination file.  In this
  particular situation, "jenkins" is the owner of the source files and
  "builder" is the owner of the destination directory (trtl/results).

jlongstaf/f5-openstack-lbaasv2-driver,richbrowne/f5-openstack-lbaasv2-driver,jputrino/f5-openstack-lbaasv2-driver,F5Networks/f5-openstack-lbaasv2-driver,F5Networks/f5-openstack-lbaasv2-driver,jputrino/f5-openstack-lbaasv2-driver,jlongstaf/f5-openstack-lbaasv2-driver,richbrowne/f5-openstack-lbaasv2-driver