shill: Turn off FastReauth on supplicant at startup

This change disables TLS session resumption for EAP-TLS 802.1x
network connections.  Some versons of freeradius, for example,
reply with an improper response when session resumption is
proposed by the client, and causes wpa_supplicant to offline
the connection.  The user experience when this interaction is
triggered is that the network connection fails.  This decision
will be revisited when newer versions of wpa_supplicant account
for this interaction issue.

BUG=chromium-os:25497
TEST=Manual -- request wpa_supplicant state before and after shill
startup via DBus:
dbus-send --system --dest=fi.w1.wpa_supplicant1 --print-reply
/fi/w1/wpa_supplicant1/Interfaces/0 org.freedesktop.DBus.Properties.Get
string:fi.w1.wpa_supplicant1.Interface string:FastReauth

Change-Id: I18bd6a0470f86c6e99e21d00c0880e52c642bb16
Reviewed-on: https://gerrit.chromium.org/gerrit/15059
Commit-Ready: Paul Stewart <pstew@chromium.org>
Reviewed-by: Paul Stewart <pstew@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
diff --git a/supplicant_interface_proxy.h b/supplicant_interface_proxy.h
index 1bc5546..a021175 100644
--- a/supplicant_interface_proxy.h
+++ b/supplicant_interface_proxy.h
@@ -36,6 +36,7 @@
   virtual void Scan(
       const std::map<std::string, ::DBus::Variant> &args);
   virtual void SelectNetwork(const ::DBus::Path &network);
+  virtual void SetFastReauth(bool enabled);
 
  private:
   class Proxy : public fi::w1::wpa_supplicant1::Interface_proxy,