Add python-mysqldb to keystone apt package list.

- Fixes bug 957065.

Change-Id: If811a725c2348cebfb326e08ef69909905e46420
diff --git a/files/apts/keystone b/files/apts/keystone
index 94479c9..ce536bf 100644
--- a/files/apts/keystone
+++ b/files/apts/keystone
@@ -7,6 +7,7 @@
 sqlite3
 python-pysqlite2
 python-sqlalchemy
+python-mysqldb
 python-webob
 python-greenlet
 python-routes