Update linkproperties after proxy is set

Telephony will set http proxy configured in default apn after
data call is success. NetworkAgent is updating linkproperties
as soon as data call response is received. Http proxy set later
is not updated.

Resend linkproperties after proxy is set.

Change-Id: Ifd6cd448e70a4467fc19a0cb18129802766947e8
CRs-Fixed: 777933