Fix typo

qubesadmin/backup/core3.py

@@ -18,7 +18,7 @@
 # You should have received a copy of the GNU Lesser General Public License along
 # with this program; if not, see <http://www.gnu.org/licenses/>.
 
-'''Parser for core2 qubes.xml'''
+'''Parser for core3 qubes.xml'''
 
 import xml.parsers
 import logging