Sometimes inline comments have no associated diff lines

[jcansdale]

• GitHub Extension for Visual Studio version: 2.4.0 (dev)
• Visual Studio version: 2015

What happened (with steps, logs and screenshots, if possible)

An exception was thrown on this line:

VisualStudio/src/GitHub.InlineReviews/Models/InlineCommentThreadModel.cs

Line 54 in 975816e

public DiffChangeType DiffLineType => DiffMatch.First().Type;

This is the inline comment that has no diff line context: grokys/PullRequestSandbox#24 (review)

    Body: "comment on main"
    CommitId: "080d67f93efeb557f8bb24a009effb85bde353aa"
    CreatedAt: {01/06/2017 13:55:49 +00:00}
    DiffHunk: "@@ -10,7 +10,6 @@ class Program"
    Id: 119620146
    OriginalCommitId: "b328e39e53c85ea15208a60c7af74698d3e146d2"
    OriginalPosition: 6
    Path: "PullRequestSandbox/Program.cs"
    Position: 0
    User: Account: Login: jcansdale IsUser: True