remove side effect in Util.format to fix bug `some function will modify passed arguments`.

lib/dialects/postgres/query-generator.js

@@ -547,7 +547,7 @@ module.exports = (function() {
         result = smth
       }
       else if (Array.isArray(smth)) {
-        result = Utils.format(smth.slice(0), "postgres")
+        result = Utils.format(smth, "postgres")
       }
 
       return result

lib/utils.js

@@ -55,7 +55,7 @@ var Utils = module.exports = {
   },
   format: function(arr, dialect) {
     var timeZone = null;
-    return SqlString.format(arr.shift(), arr, timeZone, dialect)
+    return SqlString.format(arr[0], arr.slice(1), timeZone, dialect)
   },
   formatNamedParameters: function(sql, parameters, dialect) {
     var timeZone = null;