You can do the following:
1. Spawn the Hue shell:
export HUE_CONF_DIR="/var/run/cloudera-scm-agent/process/`ls -alrt /var/run/cloudera-scm-agent/process | grep HUE | tail -1 | awk '{print $9}'`"
cd /opt/cloudera/parcels/CDH/lib/hue (or /usr/lib/hue if using packages)
./build/env/bin/hue shell
2. Paste the following python in the shell replacing <username> with the user you want to become superuser:
from django.contrib.auth.models import User
a = User.objects.get(username='<username>')
a.is_staff = True
a.is_superuser = True
a.save()