VOL-2185:Handle ProbeDeviceCapabilities_ failure

Change-Id: I61c00b57c113a05e6b996b4e932b1da05cf972da
diff --git a/agent/common/main.cc b/agent/common/main.cc
index a18db3c..49d1175 100644
--- a/agent/common/main.cc
+++ b/agent/common/main.cc
@@ -99,7 +99,12 @@
         }
     }
 
-    ProbeDeviceCapabilities_();
+    status = ProbeDeviceCapabilities_();
+    if (!status.ok()) {
+        std::cout << "ERROR: Could not find the OLT Device capabilities" << std::endl;
+        return 1;
+    }
+
     sleep(2);
     // Enable all PON interfaces. 
     for (int i = 0; i < NumPonIf_(); i++) {