Fix check_resid_tv behavior

[udovichenko]

Hi,

I found that check_resid_tv option was not working as expected.

Expected behavior

I expected that when check_resid is set to @TV and check_resid_TV value is falsy (0 or empty), migxdbTV grid will show all existing items without checking if it is connected to current resource id.

Problem

In my project with such setup, function checkForConnectedResource was always returning true, and page with falsy check_resid_TV showed none items.
I found out that in old code $check_resid is never falsy, because it can be set to (falsy) $check only if $check is truthy.

Solution

After proposed changes migxdb grid in my project works as expected:

• Shows all items when check_resid_tv is falsy in current resource
• Show only items, that are connected by resource_id, when check_resid_tv is truthy