fix function _showApplications()

[boris-gu]

Now the function looks like this:

_showApplications() {
        this._rippleAnimation();
        Main.overview.viewSelector._toggleAppsPage();
}

But instead of closing the application menu it opens the overview.
This code works well for me.

_showApplications() {
        this._rippleAnimation();
        if (! Main.overview.viewSelector._showAppsButton.checked)
        {
                Main.overview.viewSelector._toggleAppsPage();
        }
        else
        {
                Main.overview.hide();
        }
}

Why not change?