Remove unsupported ja_JP translations

locale/ja_JP.po

@@ -1,31 +0,0 @@
-#
-msgid ""
-msgstr "Content-Type: text/plain; charset=utf-8\n"
-
-msgctxt "field:product.price_list.line,end_date:"
-msgid "End Date"
-msgstr ""
-
-msgctxt "field:product.price_list.line,start_date:"
-msgid "Start Date"
-msgstr ""
-
-msgctxt "field:product.price_list.line.context,date:"
-msgid "Date"
-msgstr ""
-
-msgctxt "field:product.price_list.line.context,id:"
-msgid "ID"
-msgstr ""
-
-msgctxt "model:ir.action,name:act_price_list_line_form"
-msgid "Lines"
-msgstr "Lines"
-
-msgctxt "model:ir.model.button,string:price_list_open_lines_button"
-msgid "Open Lines"
-msgstr "Open Lines"
-
-msgctxt "model:product.price_list.line.context,name:"
-msgid "Price List Line Context"
-msgstr ""