media paused only on 'Low Battery' notification, not 'Battery Critical' notification

Steps to reproduce:

1. Open the music app from the click scope
2. Play a track
3. Enable the mock battery with:

gdbus call --session --dest "com.canonical.indicator.power" \
             --object-path /com/canonical/indicator/power/Testing \
             --method org.freedesktop.DBus.Properties.Set \
             com.canonical.indicator.power.Testing \
             MockBatteryEnabled \
             "<true>"

4. Make sure the battery level is set above low and then set it to critical:

gdbus call --session --dest "com.canonical.indicator.power" \
             --object-path /com/canonical/indicator/power/Testing \
             --method org.freedesktop.DBus.Properties.Set \
             com.canonical.indicator.power.Testing \
             MockBatteryLevel \
             "<uint32 50>"
gdbus call --session --dest "com.canonical.indicator.power" \
             --object-path /com/canonical/indicator/power/Testing \
             --method org.freedesktop.DBus.Properties.Set \
             com.canonical.indicator.power.Testing \
             MockBatteryLevel \
             "<uint32 1>"

Expected result:

A Battery critical notification appears and sound and video pauses during the notification

Actual result:

Sound and video continues playing during the notification

Note that if we set the level to 10 instead in step 4 then audio and video is paused

ProblemType: Bug
DistroRelease: Ubuntu RTM 14.09
Package: media-hub 2.0.0+14.10.20141015-0ubuntu1
Uname: Linux 3.4.67 armv7l
ApportVersion: 2.14.7-0ubuntu5
Architecture: armhf
Date: Thu Oct 16 07:38:34 2014
InstallationDate: Installed on 2014-10-16 (0 days ago)
InstallationMedia: Ubuntu Utopic Unicorn (development branch) - armhf (20141016-010328)
SourcePackage: media-hub
UpgradeStatus: No upgrade log present (probably fresh install)