B #5887: skip volatile disks on MP import (#2185)

(cherry picked from commit f1beecd07e8392e737e2161d0c7e119c8cf20b6a)

src/oca/ruby/opennebula/template_ext.rb

@@ -68,6 +68,8 @@ module OpenNebula::TemplateExt
 
                     image = image_lookup(disk)
 
+                    next unless image
+
                     if OpenNebula.is_error?(image)
                         logger.fatal image.message if logger
 
@@ -318,6 +320,9 @@ module OpenNebula::TemplateExt
                     uname = disk['IMAGE_UNAME']
                     uname ||= self['UNAME']
 
+                    # Volatile disk
+                    return unless name
+
                     name.gsub!('"', '')
                     image = @image_lookup_cache.find do |v|
                         v['NAME'] == name && v['UNAME'] == uname