[Twisted-web] minor compile/typo fix

[Andrea Arcangeli]

This fixed a compilation problem for me. I didn't actually check the
correctness of the code, so this needs checking.

Index: twisted/web2/requtil.py
===================================================================
--- twisted/web2/requtil.py	(revision 12831)
+++ twisted/web2/requtil.py	(working copy)
@@ -59,8 +59,8 @@
             return request.site.getSession(sessionCookie)
         except KeyError:
             pass
-    session = Session(request.site, request.site.mkuid()
-    site.setSession(session)
+    session = Session(request.site, request.site.mkuid())
+    request.site.setSession(session)
     request.addCookie(cookiename, session.uid, path='/')
     request.setComponent(ISession, session) # is this needed?
     return session