Remove dead is_method_error code

According to
https://lists.ozlabs.org/pipermail/openbmc/2018-October/013696.html,
The is_method_error() function will never return true
and can be removed.

Change-Id: I9f86e979ddd1854e9c98c23a3a235bc4adbd79f4
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/dbus.cpp b/dbus.cpp
index f0eb0b9..aee1654 100644
--- a/dbus.cpp
+++ b/dbus.cpp
@@ -41,16 +41,7 @@
 
     auto reply = bus.call(method);
 
-    if (reply.is_method_error())
-    {
-        log<level::ERR>("Failed to get managed objects",
-                        entry("SERVICE=%s", service.c_str()),
-                        entry("PATH=%s", objPath.c_str()));
-    }
-    else
-    {
-        reply.read(interfaces);
-    }
+    reply.read(interfaces);
 
     return interfaces;
 }
@@ -67,17 +58,7 @@
     method.append(interface);
     auto reply = bus.call(method);
 
-    if (reply.is_method_error())
-    {
-        log<level::ERR>("Failed to get all properties",
-                        entry("SERVICE=%s", service.c_str()),
-                        entry("PATH=%s", objPath.c_str()),
-                        entry("INTERFACE=%s", interface.c_str()));
-    }
-    else
-    {
-        reply.read(properties);
-    }
+    reply.read(properties);
 
     return properties;
 }
@@ -94,15 +75,7 @@
     method.append(std::vector<std::string>({interface}));
     auto reply = bus.call(method);
 
-    if (reply.is_method_error())
-    {
-        log<level::ERR>("Failed to get subtree", entry("ROOT=%s", root.c_str()),
-                        entry("INTERFACE=%s", interface.c_str()));
-    }
-    else
-    {
-        reply.read(tree);
-    }
+    reply.read(tree);
 
     return tree;
 }