Changed INSTALL to use 'python' instead of 'python2.3'

git-svn-id: http://code.djangoproject.com/svn/django/trunk@1910 bcc190cf-cafb-0310-a4f2-bffc1f526a37

INSTALL

@@ -1,7 +1,7 @@
 Thanks for downloading Django.
 
-To install it, make sure you have Python 2.3+ installed. Then run this command:
+To install it, make sure you have Python 2.3 or greater installed. Then run this command:
 
-python2.3 setup.py install
+python setup.py install
 
-For more detailed instructions, see docs/install.txt.
+For more detailed instructions, see docs/install.txt.