Thomas Haller authored Nov 06, 2013 and Dan Williams committed Nov 08, 2013

Slaves should get sorted after their masters so that when generating
connections, the NMManager knows about the masters already.

The convoluted logic here is to ensure that:

1) the kernel doesn't pass bad information that causes NM to crash
or infinite loop

2) that with complicated parent/child relationships (like a VLAN interface
with a parent that is also a slave), children always get sorted after
*all* of their ancestors.  The previous code was only sorting children
after their immediate parent/master's ifindex, but not actually after
the parent in the returned list.