Stop using deprecated defusedxml.cElementTree

defusedxml.cElementTree was deprecated in defusedxml 0.7.0[1] .

[1] https://pypi.org/project/defusedxml/#defusedxml-0-7-0rc2

Change-Id: Ic51de5ba8179708c946e42b9f2e504750c57710e

glance/async_/flows/ovf_process.py

@@ -19,10 +19,7 @@ import shutil
 import tarfile
 import urllib
 
-try:
-    from defusedxml import cElementTree as ET
-except ImportError:
-    from defusedxml import ElementTree as ET
+from defusedxml import ElementTree as etree
 
 from oslo_config import cfg
 from oslo_log import log as logging
@@ -194,7 +191,7 @@ class OVAImageExtractor(object):
 
         disk_filename, file_elements, file_ref = None, None, None
         properties = {}
-        for event, elem in ET.iterparse(ovf):
+        for event, elem in etree.iterparse(ovf):
             if event == 'end':
                 ns, tag = _get_namespace_and_tag(elem.tag)
                 if ns in CIM_NS and tag in self.interested_properties:

requirements.txt

@@ -1,5 +1,5 @@
 pbr>=3.1.1 # Apache-2.0
-defusedxml>=0.6.0 # PSF
+defusedxml>=0.7.1 # PSF
 
 # < 0.8.0/0.8 does not work, see https://bugs.launchpad.net/bugs/1153983
 SQLAlchemy>=1.3.14 # MIT