[ActionsView] Fix the regression that doesn't show 'No limit'.

With The previous commit: 68d58288c2a3, the timeout value is shown
as number even if the is unlimited. This changed the behavior and
the regression. This patch resolves it.
Merge pull request #647 from project-hatohol/fix-wrong-handling-as-sec-for-action-3

[ActionsView] Fix the regression that doesn't show 'No limit'.