logging: switch networkd static_library to lg2

This commit switches logging to lg2 in the following files -
1. src/network_manager.cpp
2. src/util.cpp
3. src/ethernet_interface.cpp

Tested: Build passes with "ninja -C build".
Change-Id: Ib2492116ecf3f41f9cd0146dc4b5389a59bce87c
Signed-off-by: Jagpal Singh Gill <paligill@gmail.com>
3 files changed