Update Interval when timeRemaining is updated

A typical watchdog implementation would give these 2 features:
  - Setting the interval
  - Resetting the timer which also means poke

This watchdog implementation does not provide a poke function
and the same can be achieved by clients making these dbus calls
in that order.

  1) Get the Last set Interval
  2) Set TimeRemaining field to result from #1

To achieve #1, this commit adds the support.

This would make sure that the new timer would expire after last
updated user interval from that time.

Fixes openbmc/openbmc#767

Change-Id: I7393eb32992d7a08518ef463fd0a442df0772392
Signed-off-by: Vishwanatha Subbanna <vishwa@linux.vnet.ibm.com>
diff --git a/watchdog.cpp b/watchdog.cpp
index 0c82df1..8c019a3 100644
--- a/watchdog.cpp
+++ b/watchdog.cpp
@@ -90,6 +90,9 @@
         log<level::INFO>("watchdog: reset timer",
                          entry("VALUE=%llu", value));
 
+        // Update Interval in Base class.
+        this->interval(value);
+
         // Update Base class data.
         return WatchdogInherits::timeRemaining(value);
     }