perf: Fix hist_entry__tui_annotate() build failure

When compiling perf on latest tip/master I see the following
error:

  cc1: warnings being treated as errors
  util/newt.c: In function 'hist_entry__tui_annotate':
  util/newt.c:764: warning: 'ret' is used uninitialized in
  this function make: *** [util/newt.o] Error 1

I think the problem was introduced by commit
13f499f0

Below is a patch that fixes the problem.
Signed-off-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <20100629173226.GC23231@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

tools/perf/util/newt.c

@@ -753,7 +753,7 @@ int hist_entry__tui_annotate(struct hist_entry *self)
 
 	browser.width += 18; /* Percentage */
 	ui_browser__show(&browser, self->ms.sym->name);
-	ui_browser__run(&browser, &es);
+	ret = ui_browser__run(&browser, &es);
 	newtFormDestroy(browser.form);
 	newtPopWindow();
 	list_for_each_entry_safe(pos, n, &head, node) {