Added some function.
- Added/Modified/Delete function for network:router_interface.
- Fixed - Delete was not working.
- There was some callback not hapening because of that the request was setting
as cancled - fixed it.
- Removed Next hop from Static route.

Change-Id: Iac06f9b1e84cb4666079f2479a3913eefb65a71c
Merge "Added some function. - Added/Modified/Delete function for network:router_interface. - Fixed - Delete was not working. - There was some callback not hapening because of that the request was setting as cancled - fixed it. - Removed Next hop from Static route."