Fix #415 crash when using 'config-set' with no parameters

ChangeLog

@@ -10,7 +10,10 @@ Deluge 0.9.07 - "1.0.0_RC7" (In Development)
   * Fix hiding the bottom pane when disabling all the tabs
   * Fix not showing new torrents if you don't use the All label first
   * Fix size units to be more accurate
- 
+
+ Null:
+  * Fix #415 crash when using 'config-set' with no parameters
+  
  Windows:
   * Fix Vista slowness issue
   * Fix properly shutting Deluge down when system shuts down

deluge/ui/null/deluge_shell.py

@@ -214,7 +214,11 @@ class CommandConfig(Command):
 
 class CommandConfigSet(Command):
     def execute(self, cmd):
-        key = cmd[1]
+        try:
+            key = cmd[1]
+        except IndexError:
+            self.usage()
+            return
 
         # Returns (correct_type, type_value)
         def convert_type(target, source):