installing most recent stealth change causes PYTHON_EGG_CACHE problem

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What steps will reproduce the problem?
1. Delete current pyodbc
2. easy_install pyodbc
3. import pyodbc

What is the expected output? What do you see instead?
I get the following error: 
ExtractionError: Can't extract file(s) to egg cache

The following error occurred while trying to extract file(s) to the Python egg
cache:

  [Error 5] Access is denied: 'C:\\Users\\jsalvatier\\AppData\\Roaming\\Python-Eggs\\pyodbc-2.1.7-py2.6-win32.egg-tmp\\pyodbc.pyd'

The Python egg cache directory is currently set to:

  C:\Users\jsalvatier\AppData\Roaming\Python-Eggs

Perhaps your account does not have write access to this directory?  You can
change the cache directory by setting the PYTHON_EGG_CACHE environment
variable to point to an accessible directory.

This bug is just a few hours old. If I swap back for a version of pyodbc that I 
deleted earlier today, it imports fine. 

I want to encourage pyodbc not to do stealth updates, but update the version 
number when the package is changed. That way these kinds of problems are easy 
to work around.

What version of the product are you using? On what operating system?
Windows 7

Please provide any additional information below.
 Python 2.6 32bit

Original issue reported on code.google.com by jsalvat...@gmail.com on 20 Aug 2010 at 9:17