ProcMount validation and testing

Signed-off-by: Serguei Bezverkhi <sbezverk@cisco.com>

pkg/apis/core/v1/defaults.go

@@ -423,3 +423,10 @@ func SetDefaults_HostPathVolumeSource(obj *v1.HostPathVolumeSource) {
 		obj.Type = &typeVol
 	}
 }
+
+func SetDefaults_SecurityContext(obj *v1.SecurityContext) {
+	if obj.ProcMount == nil {
+		defProcMount := v1.DefaultProcMount
+		obj.ProcMount = &defProcMount
+	}
+}