QA/TestCases/LUKS Enter Passphrase to unlock previously encrypted fs

Description
Support the use of encrypted filesystems for anything other than /boot using cryptsetup and LUKS. This includes install time creation/configuration, as well as integrated support in mkinitrd and initscripts (others?). Currently we are only pursuing support for encrypted devices using cryptsetup/LUKS.

When installing to a device that has an existing encrypted file system, it is necessary to prompt the user for a passphrase to unlock the encrypted filesystem for use by anaconda for a new installation.

References:
 * 1) Anaconda/Features/EncryptedBlockDevices
 * 2) Releases/FeatureEncryptedFilesystems
 * 3) Testopia case #66

Steps To Reproduce
text should look similar to: Device sda2 is encrypted. In order to access the device's contents during installation you must enter the device's passphrase below.
 * Boot anaconda on a system with a previously installed encrypted filesystem
 * Afer entering the root password, a dialog asking the user to unlock the encrypted device by entering the passphrase should appear
 * continue with installation

Expected Results

 * confirm user is presented with dialog for passphrase of pre-existing encrypted filesystem
 * after entering the passphrase, user is able to use the encrypted device for installation
 * installer completes successfully