Dont down an interface during ifreload just because the number of iface

Dont down an interface during ifreload just because the number of iface
sections for that interface changed

Testing Done: tested ifreload with new iface section

problem stmt:
if the user adds a new section for an existing interface, I mark the
interface for down.
Basically the below:

               if len(newifaceobjlist) != len(lastifaceobjlist):
                    ifacedownlist.append(ifname)
                    continue

You rarely need to add a new section to the interfaces file. It is not
recommended even by the user guide.
sankaran was trying to add a new address. Which he could have added to
the same iface section.

But, looking at his trivial example, i am thinking of not marking an
interface for down if the user merely tried to add a new section to an
existing interface
(cherry picked from commit 65c62c02981cf6e2677b18c0aafcb3f2bd737b1b)
(cherry picked from commit 4453b1921fc3f8e959131cb5e1b9e79e0433cc08)