Remove file: "XXX" i18n key

This key doesn't seem to be used.

Author: Tom Johnson

config/locales/hyrax.de.yml

@@ -1236,7 +1236,6 @@ de:
         transfer_to: Benutzer
     placeholders:
       defaults:
-        file: xxx
         find_child_work: Suche nach einer Arbeit ...
         member_of_collection_ids: Wählen Sie eine Sammlung ...
     required:

config/locales/hyrax.en.yml

@@ -1235,7 +1235,6 @@ en:
         transfer_to: User
     placeholders:
       defaults:
-        file: xxx
         find_child_work: Search for a work…
         member_of_collection_ids: Select a collection…
     required:

config/locales/hyrax.es.yml

@@ -1236,7 +1236,6 @@ es:
         transfer_to: Usuario
     placeholders:
       defaults:
-        file: xxx
         find_child_work: Busque un trabajo ...
         member_of_collection_ids: Seleccione una colección ...
     required:

config/locales/hyrax.fr.yml

@@ -1235,7 +1235,6 @@ fr:
         transfer_to: Utilisateur
     placeholders:
       defaults:
-        file: xxx
         find_child_work: Rechercher un travail ...
         member_of_collection_ids: Sélectionnez une collection ...
     required:

config/locales/hyrax.it.yml

@@ -1234,7 +1234,6 @@ it:
         transfer_to: Utente
     placeholders:
       defaults:
-        file: xxx
         find_child_work: Cerca un lavoro ...
         member_of_collection_ids: Seleziona una collezione ...
     required:

config/locales/hyrax.pt-BR.yml

@@ -1229,7 +1229,6 @@ pt-BR:
         transfer_to: Usuário
     placeholders:
       defaults:
-        file: xxx
         find_child_work: Procure uma obra ...
         member_of_collection_ids: Selecione uma coleção ...
     required:

config/locales/hyrax.zh.yml

@@ -1232,7 +1232,6 @@ zh:
         transfer_to: 用户
     placeholders:
       defaults:
-        file: XXX
         find_child_work: 搜索工作...
         member_of_collection_ids: 选择一个集合...
     required: