To support recovery of network failures during rename, the abfs client
fetches the etag of the source file, and when recovering from a
failure, uses this tag to determine whether the rename succeeded
before the failure happened.
* This works for files, but not directories
* It adds the overhead of a HEAD request before each rename.
* The option can be disabled by setting "fs.azure.enable.rename.resilience"
to false
Contributed by Sree Bhattacharyya
389b3ea6e3