Improve Python 3.x compatibility

Some mechanical translation of the deprecated
except x,y construct. Should work with Python >= 2.6
just fine

Change-Id: I394f9956b9e3e3d9f5f1e9ad50c35b13200af2a1

glanceclient/v1/shell.py

@@ -309,7 +309,7 @@ def do_image_delete(gc, args):
             if args.verbose:
                 print '[Done]'
 
-        except exc.HTTPException, e:
+        except exc.HTTPException as e:
             if args.verbose:
                 print '[Fail]'
             print '%s: Unable to delete image %s' % (e, args_image)