Continue past dependency ordering diffs.
Continue past dependency ordering diffs.

We now guard against diff returning non-zero (which it does when it
discovers changes). This allows dib-lint runs to continue past the point
of displaying a dependency ordering nit.

Change-Id: Ib7801597400d6d87146181935922c8832baf5aaa

openstack/diskimage-builder,takahashinobuyuki/diskimage-builder,CSC-IT-Center-for-Science/diskimage-builder,varunarya10/diskimage-builder,JioCloud/diskimage-builder,rdo-management/diskimage-builder,zioproto/diskimage-builder,zioproto/diskimage-builder,eantyshev/diskimage-builder,CSC-IT-Center-for-Science/diskimage-builder,openstack/diskimage-builder,NaohiroTamura/diskimage-builder,switch-ch/diskimage-builder,switch-ch/diskimage-builder,takahashinobuyuki/diskimage-builder,varunarya10/diskimage-builder,JioCloud/diskimage-builder,NaohiroTamura/diskimage-builder,rdo-management/diskimage-builder,eantyshev/diskimage-builder