bs/is: fix "Ratio has zero denominator" error with no matched accounts (#518)

hledger/Hledger/Cli/Balance.hs

@@ -532,7 +532,7 @@ balanceReportAsTable opts (MultiBalanceReport (colspans, items, (coltotals,tot,a
                 | otherwise      = (+----+ (row "" $
                                     coltotals
                                     ++ (if row_total_ opts then [tot] else [])
-                                    ++ (if average_ opts then [avg] else [])
+                                    ++ (if average_ opts   then [avg] else [])
                                     ))
 
 -- | Figure out the overall date span of a multicolumn balance report.

hledger/Hledger/Cli/BalanceView.hs

@@ -137,8 +137,7 @@ balanceviewReport BalanceView{..} CliOpts{command_=cmd, reportopts_=ropts, rawop
             sumAmts = case amts of
               a1:as -> foldl' (zipWith (+)) a1 as
               []    -> []
-            totavg  = totsum `divideMixedAmount`
-                        fromIntegral (length sumAmts)
+            totavg = totsum `divideMixedAmount` fromIntegral (length sumAmts)
             mergedTabl = case tabls of
               t1:ts -> foldl' merging t1 ts
               []    -> T.empty