Fix flavor NotFound in test_resize_server_revert_deleted_flavor

Running test_resize_server_revert_deleted_flavor with microversion > 2.46
fails with flavor NotFound error, because after microversion 2.46, 'id'
is not in server's flavor info, so we can only compare flavor details,
but if flavor is deleted, getting flavor info will throw NotFound error.
So we should save the original flavor details before flavor is deleted
for the later comparison.

Change-Id: I88cc46711d6331e7a65b17bf55e1205b333a63d0
Closes-Bug: #1892166
1 file changed