title: Upgrading numpy fails with "Permission denied" error
body: <p>I downloaded a precompiled <code>numpy</code> binary from <a href="http://www.lfd.uci.edu/~gohlke/pythonlibs/#numpy" rel="noreferrer">http://www.lfd.uci.edu/~gohlke/pythonlibs/#numpy</a> and tried upgrading my current <code>numpy</code> install on Windows 7 with</p>
  
  <pre><code>pip install --upgrade "numpy-1.10.4 vanilla-cp27-none-win32.whl"
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>C:\Users\Jeroen\AppData\Local\Enthought\Canopy\User\Scripts\pip-script.py run on 04/01/16 13:20:05
  Unpacking c:\users\jeroen\downloads\numpy-1.10.4 vanilla-cp27-none-win_amd64.whl
  Installing collected packages: numpy
  Cleaning up...
  Exception:
  Traceback (most recent call last):
    File "C:\Users\Jeroen\AppData\Local\Enthought\Canopy\User\lib\site-packages\pip\basecommand.py", line 122, in main
      status = self.run(options, args)
    File "C:\Users\Jeroen\AppData\Local\Enthought\Canopy\User\lib\site-packages\pip\commands\install.py", line 283, in run
      requirement_set.install(install_options, global_options, root=options.root_path)
    File "C:\Users\Jeroen\AppData\Local\Enthought\Canopy\User\lib\site-packages\pip\req.py", line 1435, in install
      requirement.install(install_options, global_options, *args, **kwargs)
    File "C:\Users\Jeroen\AppData\Local\Enthought\Canopy\User\lib\site-packages\pip\req.py", line 671, in install
      self.move_wheel_files(self.source_dir, root=root)
    File "C:\Users\Jeroen\AppData\Local\Enthought\Canopy\User\lib\site-packages\pip\req.py", line 901, in move_wheel_files
      pycompile=self.pycompile,
    File "C:\Users\Jeroen\AppData\Local\Enthought\Canopy\User\lib\site-packages\pip\wheel.py", line 215, in move_wheel_files
      clobber(source, lib_dir, True)
    File "C:\Users\Jeroen\AppData\Local\Enthought\Canopy\User\lib\site-packages\pip\wheel.py", line 209, in clobber
      shutil.copy2(srcfile, destfile)
    File "C:\Users\Jeroen\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.6.2.3262.win-x86_64\lib\shutil.py", line 130, in copy2
      copyfile(src, dst)
    File "C:\Users\Jeroen\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.6.2.3262.win-x86_64\lib\shutil.py", line 83, in copyfile
      with open(dst, 'wb') as fdst:
  IOError: [Errno 13] Permission denied: 'C:\\Users\\Jeroen\\AppData\\Local\\Enthought\\Canopy\\User\\Lib\\site-packages\\numpy\\core\\multiarray.pyd'
  </code></pre>
  
  <p>Some more info about the currently installed version of <code>numpy</code> on my system:</p>
  
  <pre><code>Python 2.7.3 |EPD_free 7.3-2 (32-bit)| (default, Apr 12 2012, 14:30:37) [MSC v.1500 32 bit (Intel)] on win32
  Type "credits", "demo" or "enthought" for more information.
  &gt;&gt;&gt; import numpy
  &gt;&gt;&gt; print numpy.__version__
  1.7.1
  &gt;&gt;&gt; print numpy.__path__
  ['C:\\Python27\\lib\\site-packages\\numpy']
  </code></pre>