object-updater: Ignore ENOENT when trying to unlink stale pending files
object-updater: Ignore ENOENT when trying to unlink stale pending files

Change-Id: Iaac1fb891d70707af38c567d9cca5913b8355b7d
Closes-Bug: #1877924

openstack/swift,tipabu/swift,swiftstack/swift,openstack/swift,openstack/swift,tipabu/swift,swiftstack/swift,openstack/swift,tipabu/swift,swiftstack/swift,tipabu/swift