libweave: Fix wifi bootstrapping

We mistakenly go out of bootstrapping mode if any network change
is detected (even "transitions" like offline -> offline).

We only need to go from bootstrapping mode into monitoring when
network connection detects that there is network.

BUG=brillo:1233
TEST=`FEATURES=test emerge-link libweave`

Change-Id: I7afc715152fc3a2be5a53926c4e3b71c0d22cb79
Reviewed-on: https://chromium-review.googlesource.com/293023
Reviewed-by: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Commit-Queue: Vitaly Buka <vitalybuka@chromium.org>
Tested-by: Vitaly Buka <vitalybuka@chromium.org>

libweave/src/privet/wifi_bootstrap_manager.cc

diff --git a/libweave/src/privet/wifi_bootstrap_manager.cc b/libweave/src/privet/wifi_bootstrap_manager.cc
index 84ceb3e..bea033f 100644
--- a/libweave/src/privet/wifi_bootstrap_manager.cc
+++ b/libweave/src/privet/wifi_bootstrap_manager.cc
@@ -232,7 +232,7 @@
   VLOG(3) << "ConnectivityChanged: " << is_connected;
   UpdateConnectionState();
 
-  if (state_ == State::kBootstrapping) {
+  if (state_ == State::kBootstrapping && is_connected) {
     StartMonitoring();
     return;
   }