Tweak site_dirs detection so that distros with weird layouts (e.g.

/usr/lib64 patches on 64-bit Fedora) will have a better chance of
working "out of the box".

--HG--
branch : setuptools
extra : convert_revision : svn%3A6015fed2-1504-0410-9fe1-9d1591cc4771/sandbox/trunk/setuptools%4042299

setuptools/command/easy_install.py

@@ -934,12 +934,12 @@ def get_site_dirs():
                                          sys.version[:3],
                                          'site-packages'))
 
+         site_lib = get_python_lib(prefix=prefix or None)
+         if site_lib not in sitedirs: sitedirs.append(site_lib)        
+
     sitedirs = filter(os.path.isdir, sitedirs)
     sitedirs = map(normalize_path, sitedirs)
-    return sitedirs or [normalize_path(get_python_lib())] # ensure at least one
-
-
-
+    return sitedirs     # ensure at least one
 
 def expand_paths(inputs):
     """Yield sys.path directories that might contain "old-style" packages"""