[PATCH] Update swig INSTALL document for Python 2 bindings

Hi,

I overlooked that 'make clean-swig-py' doesn't remove SWIG generated
source files if build-output.mk is generated for release mode. It is
need to clean them to rebuild source files for Python 2 bindings.

So I want to update subversion/bindings/swig/INSTALL so that users don't
fall into this pitfall. Could anyone please make this better?

[[[
* subversion/bindings/swig/INSTALL
  (Step 2: Build and Install Subversion.): Add description for optional
  process needed to build Python 2 bindings.

Index: subversion/bindings/swig/INSTALL
===================================================================
--- subversion/bindings/swig/INSTALL (revision 1877407)
+++ subversion/bindings/swig/INSTALL (working copy)
@@ -141,6 +141,10 @@
 
   See Subversion's own INSTALL file for details.
 
+ If you are using Subversion distribution tarball and want to build
+ Python bindings for Python 2, you should run 'sh autogen.sh' before run
+ ./configure script to rebuild build environment as non-release mode.
+
   Make sure that Subversion's ./configure script sees your installed SWIG!
   It tries to detect SWIG near the very end of its output.
 
]]]

Thanks,

-- 
Yasuhito FUTATSUKI <futatuki_at_poem.co.jp>/<futatuki_at_yf.bsdclub.org>