loleaflet expect a BCP47 language tag syntax while OC.getLocale returns
a lanugage tag where subtags are separated by '_' instead of '-'
(BCP47).
It seems safe to just replace '_' with '-' before feeding it to
loleaflet
(cherry picked from commit 5596ae17ce3610ebb23f7709112fdcaa314efc28)
Signed-off-by: Andras Timar <andras.timar@collabora.com>
f790f640b1