Don't be so strict when retrieving content items & result items within verify_results() routine

Current implementation retrieved just OVAL IDs prefixed with "oval:1". Doing so
might skip some tests (e.g. textfilecontent54 or systemd* probes ones) from
evaluation.
Update RHEL6 OVAL file to ignore world-writable files in /proc/ directory

 * This change is made in reference to message in SSG [1]
 * Kernel people says that files have write flag, but they are not writable,
   so it is ok.

[1] https://lists.fedorahosted.org/pipermail/scap-security-guide/2014-May/005512.html