virsh: Resolve Coverity DEADCODE

Use 'dead_error_condition' instead of 'dead_error_begin'

tools/virsh.c

@@ -118,7 +118,7 @@ virshCatchDisconnect(virConnectPtr conn,
         case VIR_CONNECT_CLOSE_REASON_KEEPALIVE:
             str = N_("Disconnected from %s due to keepalive timeout");
             break;
-        /* coverity[dead_error_begin] */
+        /* coverity[dead_error_condition] */
         case VIR_CONNECT_CLOSE_REASON_CLIENT:
         case VIR_CONNECT_CLOSE_REASON_LAST:
             break;