net: Use C++11 member initialization in protocol
Summary:
This change removes Init from the constructors and instead uses C++11 member initialization. This removes a bunch of boilerplate, makes the code easier to read. Also, C++11 member initialization avoids accidental uninitialized members.
Backport of core PR19020.
Test Plan:
ninja all check-all
Reviewers: #bitcoin_abc, majcosta
Reviewed By: #bitcoin_abc, majcosta
Differential Revision: https://reviews.bitcoinabc.org/D9190