Add PostgreSQL pod name Scalyr sidecar environment (#194)

This will allow the Scalyr image to add a custom attribute to shipped
log entries that notes the name of the originating pod.

pkg/cluster/k8sres.go

@@ -445,6 +445,15 @@ func (c *Cluster) generatePodTemplate(
 				Resources:       *resourceRequirementsScalyrSidecar,
 				VolumeMounts:    volumeMounts,
 				Env: []v1.EnvVar{
+					{
+						Name: "POD_NAME",
+						ValueFrom: &v1.EnvVarSource{
+							FieldRef: &v1.ObjectFieldSelector{
+								APIVersion: "v1",
+								FieldPath:  "metadata.name",
+							},
+						},
+					},
 					{
 						Name:  "SCALYR_API_KEY",
 						Value: c.OpConfig.ScalyrAPIKey,