Correct exception handling

Author: Dougal Ballantyne

cli/cfncluster/cfnconfig.py

@@ -248,14 +248,15 @@ def __init__(self, args):
         except AttributeError:
             pass
 
-        if self.args.extra_parameters is not None:
-            try:
+        # Handle extra parameters supplied on command-line
+        try:
+            if self.args.extra_parameters is not None:
                 self.parameters = dict(self.parameters)
                 self.__temp_dict = dict(self.parameters.items() + self.args.extra_parameters.items())
                 self.__dictlist = []
                 for key, value in self.__temp_dict.iteritems():
                     temp = [str(key),str(value)]
                     self.__dictlist.append(temp)
                 self.parameters = self.__dictlist
-            except AttributeError:
-                pass
+        except AttributeError:
+            pass