Last pieces of self-call support.

The last few pieces of the hack that lets us use trans.trans_call() to
translate self-calls, plus a fix for the parser buy that was
preventing self-call expressions from getting past parsing.
test/run-pass/obj-self.rs works now (as in it actually prints "hi!"
twice!).

src/comp/front/parser.rs

@@ -899,7 +899,7 @@ impure fn parse_bottom_expr(parser p) -> @ast.expr {
                                            some(token.COMMA),
                                            pf, p);
             hi = es.span;
-            auto ex = ast.expr_call_self(e, es.node, ast.ann_none);
+            ex = ast.expr_call_self(e, es.node, ast.ann_none);
         }
 
         case (_) {