ecryptfs-recover-private doesn't fail if invalid key is provided

Bug Description

Invoking `sudo ecryptfs-recover-private /path/to/encrypted/home/` produces

INFO: Found [/mnt/sdd1/sda5-restore/@home/richter/].
Try to recover this directory? [Y/n]:
INFO: Could not find your wrapped passphrase file.
INFO: To recover this directory, you MUST have your original MOUNT passphrase.
INFO: When you first setup your encrypted private directory, you were told to record
INFO: your MOUNT passphrase.
INFO: It should be 32 characters long, consisting of [0-9] and [a-f].

Enter your MOUNT passphrase:
INFO: Success! Private data mounted at [/tmp/ecryptfs.U3NoW30S].

and mounts an empty directory although the password is wrong and `/path/to/encrypted/home/` doesn't point to an `ecryptfs` directory.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: ecryptfs-utils 106-0ubuntu1
ProcVersionSignature: Ubuntu 3.19.0-10.10-generic 3.19.2
Uname: Linux 3.19.0-10-generic x86_64
ApportVersion: 2.16.2-0ubuntu4
Architecture: amd64
CasperVersion: 1.356
CurrentDesktop: Unity
Date: Thu Apr 2 19:03:35 2015
LiveMediaBuild: Ubuntu 15.04 "Vivid Vervet" - Beta amd64 (20150326)
ProcEnviron:
TERM=xterm
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: ecryptfs-utils
UpgradeStatus: No upgrade log present (probably fresh install)

See below:
https://bugs.launchpad.net/ubuntu/+source/ecryptfs-utils/+bug/1001933
https://bugs.launchpad.net/ubuntu/+source/ecryptfs-utils/+bug/1028532

However, the "bug" has been fixed. I'm going to assign to me :-)

Jason

Fix committed to lp:ecryptfs as r892.

While the fix doesn't fail if an invalid key is provided, it warns the user of the possible situation where the mount was successful but the files are not decrypted.