Change the pointer type of ip address object
Change the pointer type of ip address object

Make the ip address pointer shared as it was declared as shared,
but during creation of object it was being created as
unique.
It is required to be shared as the ip addresses
is being exposed through API to network manager.

Change-Id: Id520e89b1105dddb7178be638ce708eeeefa5be3
Signed-off-by: Ratan Gupta <a42a43504c26cfe5294e3d72712325cd74a43440@in.ibm.com>

openbmc/phosphor-networkd,openbmc/phosphor-networkd