PEP8 type comparison cleanup

Fixes bug #910295

The None, True, and False values are singletons.

All variable *comparisons* to singletons should use 'is' or 'is not'.
All variable *evaluations* to boolean should use 'if' or 'if not'.

"== None", "== True", "== False", and "!= None" comparisons in sqlalchemy's
where(), or_(), filter(), and_(), and select() functions should not be changed.

Incorrect comparisons or evaluations in comments were not changed.

Change-Id: I087f0883bf115b5fe714ccfda86a794b9b2a87f7

2 files changed, 6 insertions, 6 deletions

diff --git a/nova/virt/images.py b/nova/virt/images.py
index e088a92b3..b884e5124 100644
--- a/nova/virt/images.py
+++ b/nova/virt/images.py
@@ -69,7 +69,7 @@ def fetch_to_raw(context, image_href, path, user_id, project_id):
     data = _qemu_img_info(path_tmp)
 
     fmt = data.get("file format", None)
-    if fmt == None:
+    if fmt is None:
         os.unlink(path_tmp)
         raise exception.ImageUnacceptable(
             reason=_("'qemu-img info' parsing failed."), image_id=image_href)
diff --git a/nova/virt/xenapi/volumeops.py b/nova/virt/xenapi/volumeops.py
index f9ba17fe6..0bce133ef 100644
--- a/nova/virt/xenapi/volumeops.py
+++ b/nova/virt/xenapi/volumeops.py
@@ -61,7 +61,7 @@ class VolumeOps(object):
 
     def delete_volume_for_sm(self, vdi_uuid):
         vdi_ref = self._session.call_xenapi("VDI.get_by_uuid", vdi_uuid)
-        if vdi_ref == None:
+        if vdi_ref is None:
             raise exception.Error(_('Could not find VDI ref'))
 
         try:
@@ -73,10 +73,10 @@ class VolumeOps(object):
     def create_sr(self, label, params):
         LOG.debug(_("Creating SR %s") % label)
         sr_ref = VolumeHelper.create_sr(self._session, label, params)
-        if sr_ref == None:
+        if sr_ref is None:
             raise exception.Error(_('Could not create SR'))
         sr_rec = self._session.call_xenapi("SR.get_record", sr_ref)
-        if sr_rec == None:
+        if sr_rec is None:
             raise exception.Error(_('Could not retrieve SR record'))
         return sr_rec['uuid']
 
@@ -89,7 +89,7 @@ class VolumeOps(object):
             return sr_ref
         sr_ref = VolumeHelper.introduce_sr(self._session, sr_uuid, label,
                                            params)
-        if sr_ref == None:
+        if sr_ref is None:
             raise exception.Error(_('Could not introduce SR'))
         return sr_ref
 
@@ -103,7 +103,7 @@ class VolumeOps(object):
     # Checks if sr has been introduced
     def forget_sr(self, sr_uuid):
         sr_ref = VolumeHelper.find_sr_by_uuid(self._session, sr_uuid)
-        if sr_ref == None:
+        if sr_ref is None:
             LOG.INFO(_('SR %s not found in the xapi database') % sr_uuid)
             return
         try: