shill: reduce delay between scans, when supplicant reports
"No suitable network".

BUG=chromium-os:27309
TEST=WiFiRomaing.001SSIDSwitchBack

Change-Id: Idd738f737abfdbdcf1e79aff21f860b5b52f1110
Reviewed-on: https://gerrit.chromium.org/gerrit/18021
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Tested-by: mukesh agrawal <quiche@chromium.org>
Commit-Ready: mukesh agrawal <quiche@chromium.org>
diff --git a/supplicant_interface_proxy_interface.h b/supplicant_interface_proxy_interface.h
index 0298a4e..bf60d04 100644
--- a/supplicant_interface_proxy_interface.h
+++ b/supplicant_interface_proxy_interface.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
+// Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
@@ -29,6 +29,7 @@
       const std::map<std::string, ::DBus::Variant> &args) = 0;
   virtual void SelectNetwork(const ::DBus::Path &network) = 0;
   virtual void SetFastReauth(bool enabled) = 0;
+  virtual void SetScanInterval(int seconds) = 0;
 };
 
 }  // namespace shill