Fixes running 'hg serve' with Windows executable and no explicit template path configured.

PY2EXE executables don't support __file__ but do place the directory of the
shared code library into sys.prefix.

Fixes bug 152.

mercurial/hgweb.py

@@ -20,6 +20,10 @@ def templatepath():
         p = os.path.join(os.path.dirname(__file__), f)
         if os.path.isdir(p):
             return os.path.normpath(p)
+    else:
+       # executable version (py2exe) doesn't support __file__
+        if hasattr(sys, 'frozen'):
+            return os.path.join(sys.prefix, "templates")
 
 def age(x):
     def plural(t, c):