Remove unsupported ja_JP translations

locale/ja_JP.po

@@ -1,19 +0,0 @@
-#
-msgid ""
-msgstr "Content-Type: text/plain; charset=utf-8\n"
-
-msgctxt "model:ir.action,name:act_invoice_line_in_form"
-msgid "Supplier Invoice Lines"
-msgstr "Supplier Invoice Lines"
-
-msgctxt "model:ir.action,name:act_invoice_line_out_form"
-msgid "Invoice Lines"
-msgstr "Invoice Lines"
-
-msgctxt "model:ir.ui.menu,name:menu_invoice_line_in_form"
-msgid "Supplier Invoice Lines"
-msgstr "Supplier Invoice Lines"
-
-msgctxt "model:ir.ui.menu,name:menu_invoice_line_out_form"
-msgid "Invoice Lines"
-msgstr "Invoice Lines"