[ypserv/f19] (3 commits) ...Return proper error code when map file opening did not succeeded RHBZ#1004110

[Honza Horak]

Summary of changes:

  c387ac8... Fix crash when netgroups include recursive dependency (*)
  d389cb0... Remove systemd-units and systemd-sysv requirements Clean-up (*)
  10cbfc5... Return proper error code when map file opening did not succ (*)

(*) This commit already existed in another branch; no separate mail sent