Closes #162
HTML attributes incorrectly localised in en_GB.po (color localized to colour) resulting in the following messages being logged:
gnome-boxes[20927]: Failed to set text '21.8 GB (200.7 kB used)' from markup due to error parsing markup: Attribute 'colour' is not allowed on the tag on line 1 char 45
@wjt fixed one instance of this in commit e0a9164a, this fixes the other.
Edited by Daniel Davies