use sdbusplus unpack syntax

Rather than defining a variable and then reading it from a message,
sdbusplus also supports directly unpack-ing from the message.  Use
this syntax instead as it is more efficient and succinct.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I311c0a4a3aa8b68ea2814c00eaff11e2e8803fb1
diff --git a/watchdog/watchdog_dbus.cpp b/watchdog/watchdog_dbus.cpp
index 204aecd..7564e40 100644
--- a/watchdog/watchdog_dbus.cpp
+++ b/watchdog/watchdog_dbus.cpp
@@ -39,8 +39,8 @@
         auto reply = bus.call(newMethod);
 
         // dbus call results
-        std::map<std::string, std::vector<std::string>> responseFindService;
-        reply.read(responseFindService);
+        auto responseFindService =
+            reply.unpack<std::map<std::string, std::vector<std::string>>>();
 
         // If we successfully found the service associated with the dbus object
         // path and interface then create a method for the specified interface
@@ -145,9 +145,8 @@
             method.append(interface, "CurrentHostState");
             auto bus = sdbusplus::bus::new_system();
             auto response = bus.call(method);
-            std::variant<std::string> reply;
+            auto reply = response.unpack<std::variant<std::string>>();
 
-            response.read(reply);
             std::string currentHostState(std::get<std::string>(reply));
 
             if (currentHostState ==
diff --git a/watchdog/watchdog_handler.cpp b/watchdog/watchdog_handler.cpp
index 5f48ac5..169be42 100644
--- a/watchdog/watchdog_handler.cpp
+++ b/watchdog/watchdog_handler.cpp
@@ -157,8 +157,7 @@
             auto response = bus.call(method);
 
             // reply will be type dbus::ObjectPath
-            sdbusplus::message::object_path reply;
-            response.read(reply);
+            auto reply = response.unpack<sdbusplus::message::object_path>();
 
             // monitor dump progress
             monitorDump(reply, dumpParameters.timeout);