Naming the default language misses some columns

[jnm]

depends on kobotoolbox/formpack#214
discussion: https://www.flowdock.com/app/kobotoolbox/support/threads/PPk29hNVryqbLTS6zWJHKpqDxOp

What happens

Upload an XLSForm like:

type	name	label	constraint	constraint_message	required	required_message	guidance_hint	hint
text	Name	What is your name?	. = 'Rabbit'	Constraint Message Check (English)	1	Required Message Check (English)	Guidance Hint Message Check (English)	Hint Message Check (English)

Click "Manage Translations", and set "Default language name" to English and "Default language code" to en. Click "SET".

Now, view the XLSForm, e.g. at https://[kpi-host]/assets/[asset-uid]/xls/, and notice that only the label and hint columns have had the ::English (en) suffix appended:

type	name	label::English (en)	hint::English (en)	required	constraint	guidance_hint	required_message	constraint_message
text	Name	What is your name?	Hint Message Check (English)	1	. = 'Rabbit'	Guidance Hint Message Check (English)	Required Message Check (English)	Constraint Message Check (English)

What's expected

guidance_hint, required_message, and constraint_message should all have ::English (en) appended. Other translatable columns may exist; verify by checking https://xlsform.org.