Typo corrections for test files in cinder

Correct the typo from follow code files:

cinder/tests/api/contrib/test_backups.py
cinder/tests/test_migrations.py
cinder/tests/test_netapp.py

Change-Id: I6aeddfee36ecd101264d73d2e90686df683cc29d

cinder/tests/api/contrib/test_backups.py

@@ -517,7 +517,7 @@ class BackupsAPITestCase(test.TestCase):
                              'disabled': 1,
                              'updated_at': timeutils.utcnow()}]
 
-        #dead service that last reported at 20th centry
+        #dead service that last reported at 20th century
         dead_service = [{'availability_zone': "fake_az", 'host': alt_host,
                          'disabled': 0, 'updated_at': '1989-04-16 02:55:44'}]
 

cinder/tests/test_migrations.py

@@ -263,7 +263,7 @@ class TestMigrations(test.TestCase):
     def test_mysql_innodb(self):
         """Test that table creation on mysql only builds InnoDB tables."""
         # add this to the global lists to make reset work with it, it's removed
-        # automaticaly in tearDown so no need to clean it up here.
+        # automatically in tearDown so no need to clean it up here.
         connect_string = _get_connect_string('mysql')
         engine = sqlalchemy.create_engine(connect_string)
         self.engines["mysqlcitest"] = engine

cinder/tests/test_netapp.py

@@ -464,7 +464,7 @@ class FakeDirectCmodeHTTPConnection(object):
         if data:
             req_str += '\r\n%s' % data
 
-        # NOTE(vish): normally the http transport normailizes from unicode
+        # NOTE(vish): normally the http transport normalizes from unicode
         sock = FakeHttplibSocket(req_str.decode("latin-1").encode("utf-8"))
         # NOTE(vish): stop the server from trying to look up address from
         #             the fake socket