Remove old python from path.

This causes conflicts when running commands with the 2.75 python
that is part of depot_tools, and we should probably be defaulting to
that everywhere anyhow, as part of the python standardization process.,

Review URL:

git-svn-id: 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
diff --git a/setup_env.bat b/setup_env.bat
index 5fe9b75..361a1ba 100755
--- a/setup_env.bat
+++ b/setup_env.bat
@@ -1,4 +1,4 @@
 :: This script adds cygwin to the path
 @echo OFF
-set PATH=%~dp0\bin;%~dp0\..\python_26;%PATH%
+set PATH=%~dp0\bin;%PATH%