One workaround posted on launchpad is a script that is based on the hooks of pm-utils:
sudo wget -O /etc/pm/sleep.d/20_kill-notify-osd https://bugs.launchpad.net/ubuntu/+source/gnome-settings-daemon/+bug/1232454/+attachment/3942236/+files/20_kill-notify-osd
sudo chmod +x /etc/pm/sleep.d/20_kill-notify-osd
Another workaround might be the following method:
Download a script and make it executable:
wget -O ~/.suspendwarning.sh https://bugs.launchpad.net/ubuntu/+source/gnome-settings-daemon/+bug/1232454/+attachment/3942095/+files/myscripts
chmod +x ~/.suspendwarning.sh
Add it to ~/.bashrc
:
echo "if [ -f ~/.suspendwarning.sh ]; then
. ~/.suspendwarning.sh
fi" >> ~/.bashrc
After logging out and in the notifications should not pop up anymore after resume.