Proprietary project creation rerendering after error is broken

[Thomi Richards]

Convo from IRC:

<thomi> blr: the second bug is.... WTF am I doing wrong here? http://static.inky.ws/image/5308/Screenshot%20from%202015-07-15%2009:06:08.png
-*- noise soft-EOD
<thomi> LP tells me there's an error, but doesn't flag anything in the UI?
--> veebers (<email address hidden>) has joined #ci
<blr> thomi: is there anything relevant in the "Possible duplicate projects" expander?
<thomi> blr: no
<cjwatson> "Other/Proprietary" should have popped up a "Licence details:" text area
<cjwatson> I suspect it's complaining that that's empty
<cjwatson> It pops up for me when I try this on qastaging
<blr> thomi: any js errors?
-*- thomi looks
<thomi> blr: yes, just one:
<thomi> Uncaught TypeError: Cannot read property 'halt' of null
<blr> could you include that in a report with the line number please?
<thomi> sure
<cjwatson> Ah, but when you submit the form it doesn't display that text area again
<cjwatson> So yeah, pretty sure that's it

Error details:

javascript/product_views-min.js:7 Uncaught TypeError: Cannot read property 'halt' of null