remove 2.2 and 2.6 compat code (closes #22200)

Patch from Thomas Kluyver.
diff --git a/Lib/distutils/command/install.py b/Lib/distutils/command/install.py
index 456511c..d768dc5 100644
--- a/Lib/distutils/command/install.py
+++ b/Lib/distutils/command/install.py
@@ -15,32 +15,17 @@
 from distutils.util import get_platform
 from distutils.errors import DistutilsOptionError
 
-# this keeps compatibility from 2.3 to 2.5
-if sys.version < "2.6":
-    USER_BASE = None
-    USER_SITE = None
-    HAS_USER_SITE = False
-else:
-    from site import USER_BASE
-    from site import USER_SITE
-    HAS_USER_SITE = True
+from site import USER_BASE
+from site import USER_SITE
+HAS_USER_SITE = True
 
-if sys.version < "2.2":
-    WINDOWS_SCHEME = {
-        'purelib': '$base',
-        'platlib': '$base',
-        'headers': '$base/Include/$dist_name',
-        'scripts': '$base/Scripts',
-        'data'   : '$base',
-    }
-else:
-    WINDOWS_SCHEME = {
-        'purelib': '$base/Lib/site-packages',
-        'platlib': '$base/Lib/site-packages',
-        'headers': '$base/Include/$dist_name',
-        'scripts': '$base/Scripts',
-        'data'   : '$base',
-    }
+WINDOWS_SCHEME = {
+    'purelib': '$base/Lib/site-packages',
+    'platlib': '$base/Lib/site-packages',
+    'headers': '$base/Include/$dist_name',
+    'scripts': '$base/Scripts',
+    'data'   : '$base',
+}
 
 INSTALL_SCHEMES = {
     'unix_prefix': {