man: few fixes in documentation

- fixed title line according to man man-pages
- removed AUTHORS section, as strognly discouraged
  according to man man-pages
- addressed late comments on http://gerrit.ovirt.org/18215

Change-Id: If244dd158d1da4f58f9c84637599e9380ace4f38
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>
Reported-By: Timothy Hildred <thildred@redhat.com>