libweave: Change backup polling interval back to 30 minutes

The interval has been changed to 30 seconds by mistake when performing
code refactoring. It should be 30 minutes.

BUG: 25176346
Change-Id: I0ceb1625f733ef10f74b3c2844d4c5b30515a666
Reviewed-on: https://weave-review.googlesource.com/1390
Reviewed-by: Vitaly Buka <vitalybuka@google.com>
(cherry picked from commit c1fc90c1724427d8e926172ed258e05ff63b8e26)
Reviewed-on: https://weave-review.googlesource.com/1400

libweave/src/device_registration_info.cc

diff --git a/libweave/src/device_registration_info.cc b/libweave/src/device_registration_info.cc
index 48361b9..458b57d 100644
--- a/libweave/src/device_registration_info.cc
+++ b/libweave/src/device_registration_info.cc
@@ -41,7 +41,7 @@
 namespace {
 
 const int kPollingPeriodSeconds = 7;
-const int kBackupPollingPeriodSeconds = 30;
+const int kBackupPollingPeriodMinutes = 30;
 
 using provider::HttpClient;
 
@@ -1183,7 +1183,7 @@
   CHECK_EQ(primary_notification_channel_->GetName(), channel_name);
   notification_channel_starting_ = false;
   pull_channel_->UpdatePullInterval(
-      base::TimeDelta::FromSeconds(kBackupPollingPeriodSeconds));
+      base::TimeDelta::FromMinutes(kBackupPollingPeriodMinutes));
   current_notification_channel_ = primary_notification_channel_.get();
 
   // If we have not successfully connected to the cloud server and we have not