Fix #364. In WSH, return empty string for files not found.

Author: dmethvin

src/cli/wsh.js

@@ -122,13 +122,18 @@ var wshapi = (function(){
 
         readFile: function(path){
             var forReading = 1;
-            var tf = fso.OpenTextFile(path, forReading);
-            var allText = tf.ReadAll();
-            tf.Close();
+            var allText;
+            try {
+                var tf = fso.OpenTextFile(path, forReading);
+                allText = tf.ReadAll();
+                tf.Close();
+            } catch (ex) {
+                return "";
+            }
             return allText;
         }
     };
 
 }());
 
-cli(wshapi);
+cli(wshapi);