Use t.TempDir for SQLite databases, so tests don't rip out each others databases (#2950)

This should hopefully finally fix issues about `disk I/O error` as seen
[here](https://gitlab.alpinelinux.org/alpine/aports/-/jobs/955030/raw)

Hopefully this will also fix `SSL accept attempt failed` issues by
disabling HTTP keep alives when generating a config for CI.

internal/log_unix.go

@@ -85,6 +85,8 @@ func checkSyslogHookParams(params map[string]interface{}) {
 }
 
 func setupStdLogHook(level logrus.Level) {
+	levelLogAddedMu.Lock()
+	defer levelLogAddedMu.Unlock()
 	if stdLevelLogAdded[level] {
 		return
 	}