Bug 20141: Untranslatable string in transport cost matrix

Bug 20141: Untranslatable string in transport cost matrix

Make the "Disable" checkboxes in transport cost matrix translatable

Test plan:

1) Go to Home -> Administration -> Transport cost matrix
2) Click on any cell
3) Note the "Disable" checkbox text
4) Install patch, add a language, translate the text, etc
5) Repeat 1-3, the "Disable" text should now be translated

Signed-off-by: Pasi Kallinen <pasi.kallinen@joensuu.fi>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>