Dont follow dependents during down of interfaces as part of ifreload

Dont follow dependents during down of interfaces as part of ifreload

Testing Done: tested ifreload with example in the bug

ifdown of the bridge svi was following the lowerdev and downing the
bridge. kernel implicitly deletes all svi's on bridge down.
ifup of the bridge usually handles it, but a change done in 2.5.1
was causing it not to. Thinking about this some more, its safe
to not follow dependents on down during a ifreload. This patch does
just that.
(cherry picked from commit 03f7a376aee944b4037b7b7b02a5096e9360f79e)
(cherry picked from commit aac5777ecc7d367ada0681f813fbec7f78fa80ee)