Rename some Network::State constants

Failure to Error was renamed for consistency.
Connected to Online was renamed for consistency and to avoid confusion
with similar Connecting.

BUG:24267885
Change-Id: If4c9c34a4afebb3261bbd421af4f90f91062d7a2
Reviewed-on: https://weave-review.googlesource.com/1270
Reviewed-by: Vitaly Buka <vitalybuka@google.com>
diff --git a/libweave/examples/ubuntu/netlink_network.cc b/libweave/examples/ubuntu/netlink_network.cc
index a76655a..d121fca 100644
--- a/libweave/examples/ubuntu/netlink_network.cc
+++ b/libweave/examples/ubuntu/netlink_network.cc
@@ -60,13 +60,13 @@
   auto refill_result = nl_cache_refill(nl_sock_.get(), nl_cache_.get());
   if (refill_result < 0) {
     LOG(ERROR) << "failed to refresh netlink cache: " << refill_result;
-    return Network::State::kFailure;
+    return Network::State::kError;
   }
   std::unique_ptr<rtnl_link, Deleter> nl_link{
       rtnl_link_get(nl_cache_.get(), if_index)};
   if (!nl_link) {
     LOG(ERROR) << "failed to get interface 0";
-    return Network::State::kFailure;
+    return Network::State::kError;
   }
 
   int state = rtnl_link_get_operstate(nl_link.get());
@@ -77,13 +77,13 @@
     case IF_OPER_DORMANT:
       return Network::State::kConnecting;
     case IF_OPER_UP:
-      return Network::State::kConnected;
+      return Network::State::kOnline;
     case IF_OPER_TESTING:
     case IF_OPER_NOTPRESENT:
     case IF_OPER_UNKNOWN:
     default:
       LOG(ERROR) << "unknown interface state: " << state;
-      return Network::State::kFailure;
+      return Network::State::kError;
   }
 }