fix the typo mistake

it's need  'a' here not 'an'

Change-Id: I71a800aa32f13a4d550f01dc9fcd3773f2268854

mogan/common/keystone.py

@@ -61,7 +61,7 @@ def get_session(group):
 
 
 # TODO(pas-ha) we actually should barely need this at all:
-# if we instantiate a identity.Token auth plugin from incoming
+# if we instantiate an identity.Token auth plugin from incoming
 # request context we could build a session with it, and each client
 # would know its service_type already, looking up the endpoint by itself
 @ks_exceptions

tools/test-setup.sh

@@ -18,7 +18,7 @@ DB_PW=openstack_citest
 sudo -H mysqladmin -u root password $DB_ROOT_PW
 
 # It's best practice to remove anonymous users from the database.  If
-# a anonymous user exists, then it matches first for connections and
+# an anonymous user exists, then it matches first for connections and
 # other connections from that host will not work.
 sudo -H mysql -u root -p$DB_ROOT_PW -h localhost -e "
     DELETE FROM mysql.user WHERE User='';