Fix an error while adding a dependency via UI. (Backport #5862) (#5876)

Fixes: #5783.

models/issue_comment.go

@@ -748,6 +748,9 @@ func createIssueDependencyComment(e *xorm.Session, doer *User, issue *Issue, dep
 	if !add {
 		cType = CommentTypeRemoveDependency
 	}
+	if err = issue.loadRepo(e); err != nil {
+		return
+	}
 
 	// Make two comments, one in each issue
 	_, err = createComment(e, &CreateCommentOptions{

models/issue_dependency_test.go

@@ -19,11 +19,9 @@ func TestCreateIssueDependency(t *testing.T) {
 
 	issue1, err := GetIssueByID(1)
 	assert.NoError(t, err)
-	issue1.LoadAttributes()
 
 	issue2, err := GetIssueByID(2)
 	assert.NoError(t, err)
-	issue2.LoadAttributes()
 
 	// Create a dependency and check if it was successful
 	err = CreateIssueDependency(user1, issue1, issue2)