Update the ubuntu regex

Problem:
amazon-ebs: No AMI was found matching filters: {
   Filters: [{
       Name: "name",
       Values: ["*Ubuntu*16.04*"]
     },{
       Name: "root-device-type",
       Values: ["ebs"]
     },{
       Name: "virtualization-type",
       Values: ["hvm"]
     }],
   Owners: ["099720109477"]
}

Change-Id: I46b54bda7fafade1367624261363c22ab1b4d5fa
1 file changed