Fix 12 crash in Ring-LRC. I could crash the macOS client with about half of them (https://gerrit-ring.savoirfairelinux.com/#/c/6770/ is by far the worst). The other are mostly compiler warning fixes.
Here are the Dockerfile for preventing further regressions on Gerrit https://github.com/Elv13/docker-kf5-pipeline/blob/master/docker-kf5-coverity/Dockerfile https://github.com/Elv13/docker-kf5-pipeline/blob/master/docker-kf5-clazy-scanbuild/Dockerfile
