Bug 1543077 part 3 - Remove the old Japanese detector from the tree. r=emk

Depends on D27793

Differential Revision: https://phabricator.services.mozilla.com/D27794

--HG--
extra : moz-landing-system : lando

Author: hsivonen

extensions/universalchardet/moz.build

@@ -4,7 +4,6 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-DIRS += ['src']
 TEST_DIRS += ['tests']
 
 with Files('**'):