Affected Version: 2.15-rc3-2718-gd98aece38a

The tryjob choose checkbox doesn't update when the job list changes.

What steps will reproduce the problem?
1. Click "choose tryjobs".
2. Select, say, the second entry from the top on the list.
3. Then start typing to filter the list in such a way that the selected entry moves to top.

What is the expected output?
The selected entry remains the same if it is still shown.

What do you see instead?
A different entry at the same position has the selection mark.

To clarify: if Step 2 has this list:
    [ ] chromium_presubmit
    [X] linux_chromium_compile_dbg_ng
    [ ] linux_chromium_dbg_ng
    [ ] linux_chromium_rel_ng
and in Step 3 I type "l" to see only those starting with that letter, the list shown becomes:
    [ ] linux_chromium_compile_dbg_ng
    [X] linux_chromium_dbg_ng
    [ ] linux_chromium_rel_ng