[RHEL/6] audit_rules_unsuccessful_file_modification rule:
* Fix XCCDF description to require audit 32-bit calls on 32-bit system &
  both 32-bit and 64-bit system calls on 64-bit system
* Fix OVAL check - previously it required to audit both 32-bit & 64-bit
  system calls. But there isn't a point in requiring to audit 64-bit system
  calls on 32-bit system (since this can't happen). The current version aligns
  with logic used in other system calls OVAL checks.
* Add RHEL-6 remediation script.