Simplify the registry-module-finding code: _winreg or win32api/win32con.

This'll work fine with 2.0 or 1.5.2, but is less than ideal for
1.6a1/a2.  But the code to accomodate 1.6a1/a2 was released with
Distutils 0.9, so it can go away now.

msvccompiler.py

@@ -20,10 +20,7 @@ from distutils.ccompiler import \
 
 _can_read_reg = 0
 try:
-    try:
-        import _winreg
-    except ImportError:
-        import winreg                   # for pre-2000/06/29 CVS Python
+    import _winreg
 
     _can_read_reg = 1
     hkey_mod = _winreg