Don't include missing translation in .js

It just adds size and confusion. Instead, omit any lines where no
translation is available.

app/locale/fr.json

@@ -1,5 +1,4 @@
 {
-    "HTTPS is required for full functionality": "",
     "Connecting...": "En cours de connexion...",
     "Disconnecting...": "Déconnexion en cours...",
     "Reconnecting...": "Reconnexion en cours...",
@@ -40,7 +39,6 @@
     "Reboot": "Redémarrer",
     "Reset": "Réinitialiser",
     "Clipboard": "Presse-papiers",
-    "Edit clipboard content in the textarea below.": "",
     "Settings": "Paramètres",
     "Shared Mode": "Mode partagé",
     "View Only": "Afficher uniquement",
@@ -65,12 +63,6 @@
     "Version:": "Version :",
     "Disconnect": "Déconnecter",
     "Connect": "Connecter",
-    "Server identity": "",
-    "The server has provided the following identifying information:": "",
-    "Fingerprint:": "",
-    "Please verify that the information is correct and press \"Approve\". Otherwise press \"Reject\".": "",
-    "Approve": "",
-    "Reject": "",
     "Username:": "Nom d'utilisateur :",
     "Password:": "Mot de passe :",
     "Send Credentials": "Envoyer les identifiants",

app/locale/it.json

@@ -14,8 +14,6 @@
     "Credentials are required": "Le credenziali sono obbligatorie",
     "noVNC encountered an error:": "noVNC ha riscontrato un errore:",
     "Hide/Show the control bar": "Nascondi/Mostra la barra di controllo",
-    "Drag": "",
-    "Move/Drag Viewport": "",
     "Keyboard": "Tastiera",
     "Show Keyboard": "Mostra tastiera",
     "Extra keys": "Tasti Aggiuntivi",
@@ -44,7 +42,6 @@
     "Settings": "Impostazioni",
     "Shared Mode": "Modalità condivisa",
     "View Only": "Sola Visualizzazione",
-    "Clip to Window": "",
     "Scaling Mode:": "Modalità di ridimensionamento:",
     "None": "Nessuna",
     "Local Scaling": "Ridimensionamento Locale",
@@ -61,7 +58,6 @@
     "Automatic Reconnect": "Riconnessione Automatica",
     "Reconnect Delay (ms):": "Ritardo Riconnessione (ms):",
     "Show Dot when No Cursor": "Mostra Punto quando Nessun Cursore",
-    "Logging:": "",
     "Version:": "Versione:",
     "Disconnect": "Disconnetti",
     "Connect": "Connetti",

po/po2js

@@ -32,8 +32,10 @@ if (opt.argv.length != 2) {
 
 const data = po2json.parseFileSync(opt.argv[0]);
 
-const bodyPart = Object.keys(data).filter(msgid => msgid !== "").map((msgid) => {
+const bodyPart = Object.keys(data)
-    if (msgid === "") return;
+    .filter(msgid => msgid !== "")
+    .filter(msgid => data[msgid][1] !== "")
+    .map((msgid) => {
         const msgstr = data[msgid][1];
         return "    " + JSON.stringify(msgid) + ": " + JSON.stringify(msgstr);
     }).join(",\n");