Ensure current channel is selected in Channel Detail

[sphery <mtdean@…>]

The attached patch, mythweb-channel_detail_selected_channel.patch, fixes the Channel Detail page in MythWeb such that the channel whose listings are being viewed is selected by default. The channel_select() function already had code to ensure the channel whose ID was specified in the chanid parameter was selected; however, for the Channel Detail page, the chanid is specified in the URI, rather than as a request parameter.

I do not know whether any page still uses the chanid parameter to specify the selected channel, but it looks like schedules_custom.php and schedules_manual.php are each using their own channel_select() function that accepts $chanid as an argument. The Channel Details page, channel.php, uses a channel_select() function that accepts $params (additional <select> tag attributes, such as onsubmit), and this patch simply adds another argument, $chanid.

[Rob Smith]

(In [14533]) Fixes #3929, this adds in sphery's patch (thanks muchly!) so that channel details will auto-select the correct channel from the drop down