Revert "Enable -Wsuggest-override for g++ >= 5.0.0"
This reverts commit d1d637fadd6dad68995d44101250ebbc3307ed0b.
This is far too noisy.
The correct steps for this kind of change are:
- Enable the warning locally
- Take the action recommended by the warning in the code, and push the result
- Push the warning on everyone to enforce that the code stays fixed for the future