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/wifi.h b/wifi.h
index 680457f..3363a98 100644
--- a/wifi.h
+++ b/wifi.h
@@ -169,6 +169,8 @@
   static const char kManagerErrorUnsupportedServiceMode[];
   static const time_t kMaxBSSResumeAgeSeconds;
   static const char kInterfaceStateUnknown[];
+  // Delay between scans when supplicant finds "No suitable network".
+  static const time_t kRescanIntervalSeconds;
 
   std::string CreateBgscanConfigString();
   std::string GetBgscanMethod(Error */* error */) { return bgscan_method_; }