Bug 1970277: Making sure Māori has it's macron

When fetching the language value from PHP's
locale_get_display_name() function.
Because the English verison doens't have it for some reason.

Change-Id: I33ff93c6d5bb17729a1283322e1626552bcd1747
Signed-off-by: Robert Lyon <robertl@catalyst.net.nz>