search: pins do not stay selected, making them unsearchable

[Trek Hopton]

When selecting pins on the search page to search for, some do not stay selected and therefore you cannot search for them, ie. when the are selected the form is submitted but a page is returned with them unselected in the pin drop down.

This happens when selecting AusOcean-JettyRig as the site, OilCam as the device, T0 as the pin.

Also when selecting AusOcean-JettyRig → ESP_2BAD6D → A0

I think this may happen to all pins but these are the ones I have tried, in some cases the pins are searchable since the MID stays on the page.

[Trek Hopton]

Resolved in PR #167