[LU-16527] some directory layout inheritance fixes

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Severity: 3
• Assignee: WC Triage
• Reporter: Vitaly Fertman

Description

fixes for some minor problems:

• it may happen that the depth is not set on a dir, do not consider
  depth == 0 as a real depth while checking if the root default is
  applicable;
• setdirstripe util implicitely sets max_inherit to 3 for non-striped
  dir when -i option is given but -c is not; at the same time 3 is the
  default for striped dirs only;
• getdirstripe shows inherited default layouts with max_inherit==0,
  whereas it has no sense anymore; the same for an explicitely set
  default layout on a dir/root with max_inherit==0;
• getdirstripe hides max_inherit_rr when stripe_offset != -1 as it has
  no sense and reset to 0, however it leads to user confusion;