Direct access to Netd from the bluetooth process is disallowed by
SELinux policy. This change reverts to the old behavior where IpManager
interacts with NetdService indirectly via NetworkManagementService.
Test: as follows:
- built (sailfish)
- flashed
- booted
- established bluetooth tethering to another device, ping'd 8.8.8.8
Bug: 36492299
This partially reverts commit af39244a34.
Change-Id: Icf20b1e24abf7dd3123760f8637928bde7afe06b
6e5d86f76b