Referencing a tagged image in a private registry in FROM causes an invalid error

[rcjsuen]

The extra semi-colon at the end is causing parsing problems in the validator.

FROM privateregistry.com:5000/image:tag
FROM localhost:1234/node:9
FROM 123.22.33.123:2345/user/image:tag2

$ dockerfile-utils lint Dockerfile
Line: 1
FROM privateregistry.com:5000/image:tag
                                    ^^^
Error: invalid reference format

Line: 2
FROM localhost:1234/node:9
                         ^
Error: invalid reference format

Line: 3
FROM 123.22.33.123:2345/user/image:tag2
                                   ^^^^
Error: invalid reference format