fix -Wextra warning for empty `else' body

fix -Wextra warning for empty `else' body

From faba5d52ae82239f522c108b51fa18dbb1ae9a8b Mon Sep 17 00:00:00 2001
Date: Mon, 5 Oct 2009 22:49:07 -0400
The macros XDECREF, XGIVEREF, and XGOTREF used ";" to denote an empty if
and else body, but these raised the following warning when compiled with
"gcc -Wall -Wextra":

    warning: suggest braces around empty body in an `else' statement
---
 Cython/Compiler/ModuleNode.py |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)