fix fiatBalance callers

lib/plugins.js

@@ -788,17 +788,20 @@ function checkNotification () {
 
 function checkBalances () {
   const cryptoCodes = exports.getCryptoCodes()
+  return db.devices()
+  .then(rows => {
+    const balances = []
+    cryptoCodes.forEach(cryptoCode => {
+      const minBalance = rows.map(r => exports.fiatBalance(cryptoCode, r.device_id).balance)
+      .reduce((min, cur) => Math.min(min, cur), Infinity)
 
-  const balances = []
-  cryptoCodes.forEach(cryptoCode => {
-    const balanceRec = exports.fiatBalance(cryptoCode)
-    if (!balanceRec) return
-    const rec = {fiatBalance: balanceRec.balance, cryptoCode,
-      fiatCode: deviceCurrency}
-    balances.push(rec)
+      if (!balanceRec) return
+      const rec = {fiatBalance: minBalance, cryptoCode, fiatCode: deviceCurrency}
+      balances.push(rec)
+    })
+
+    return balances
   })
-
-  return balances
 }
 
 exports.startCheckingNotification = function startCheckingNotification () {