InterfaceController::setBaseReachableTimeMs()

Add an InterfaceController::setBaseReachableTimeMs() method to set
the ARP/ND default reachable time, as configured in:

     /proc/sys/net/ipv4/{interface}/base_reachable_time_ms
     /proc/sys/net/ipv6/{interface}/base_reachable_time_ms

Bug: 18581716
Change-Id: Idc652e81396d81efe0f08bb1d6dc38bc8e554a56
diff --git a/server/InterfaceController.h b/server/InterfaceController.h
index a1a3c9e..89728b1 100644
--- a/server/InterfaceController.h
+++ b/server/InterfaceController.h
@@ -29,6 +29,7 @@
  private:
 	void setAcceptRA(const char* value);
 	void setAcceptRARouteTable(int tableOrOffset);
+	void setBaseReachableTimeMs(unsigned int millis);
 	void setIPv6OptimisticMode(const char *value);
 };