OpenStack Horizon LockFailed: failed to create /opt/stack/horizon/openstack_dashboard/local/demo.MainThread-9602

1)
Goto /opt/stack
#cd /opt/stack

2)
Check th eownser ship of all folders
#ls -l
drwxr-xr-x 10 saju saju     4096 Feb 17 12:47 cinder
drwxr-xr-x  6 saju saju      4096 Feb 17 12:48 data
drwxr-xr-x  8 saju saju     4096 Feb 17 12:47 glance
drwxr-xr-x 12 root root     4096 Feb 21 08:02 horizon <====

3)
Note: ownership of horizon is "root" since i copied that folder with "sudo".
Change ownership of horizon to "saju".
#chown -R saju:saju horizon

4)
Restart apache
#sudo service apache2 restart