Removing unnecessary pieces of code from network client

In the file "json/network_client.py" methods "update_vpnservice" and
"update_ikepolicy" does not have any significant meaning here.
All these cases are covered in the "network_client_base.py" file.
This patch implements this requirement.

Change-Id: I2fc3bbd8e1bdde9d4548d0ffba1a60c1742f7895
Merge "Removing unnecessary pieces of code from network client"