Clean /tmp after upload when using glance v2 client

When using glance v2 client, it will leave an upload
tmp file in /tmp folder, which will cause upload error
if its filesystem (in memory) is full.

Change-Id: I0a7267db894e7be4216a346752d299132df9a29a
Closes-Bug: #1689694

openstack_dashboard/api/glance.py

@@ -461,7 +461,16 @@ def image_create(request, **kwargs):
                                     {'data': data})
         else:
             def upload():
-                return glanceclient(request).images.upload(image.id, data)
+                try:
+                    return glanceclient(request).images.upload(image.id, data)
+                finally:
+                    filename = str(data.file.name)
+                    try:
+                        os.remove(filename)
+                    except OSError as e:
+                        LOG.warning('Failed to remove temporary image file '
+                                    '%(file)s (%(e)s)',
+                                    {'file': filename, 'e': e})
             thread.start_new_thread(upload, ())
 
     return Image(image)