virtcontainers: Fix structured logging in cgroups package

Call the `pkg/cgroups` package `SetLogger()` function to ensure all its log
records contain all required structured logging fields.

Fixes: #2782

Signed-off-by: Julio Montes <julio.montes@intel.com>

src/runtime/virtcontainers/pkg/cgroups/manager.go

@@ -59,6 +59,13 @@ var (
 	cgroupsLogger = logrus.WithField("source", "virtcontainers/pkg/cgroups")
 )
 
+// SetLogger sets up a logger for this pkg
+func SetLogger(logger *logrus.Entry) {
+	fields := cgroupsLogger.Data
+
+	cgroupsLogger = logger.WithFields(fields)
+}
+
 func EnableSystemdCgroup() {
 	systemd := true
 	systemdCgroup = &systemd