Actually use mAssumeSymmetricEncryption and set it to false as
default. Don't close the file input stream, so we can actually
look for PGP encrypted data in the next step.
Since the views are being reused, a revoked key might set the text
color of a view and when the view is being reused for a non-revoked
key it is still red. So grab the default text colour and set it
explicitly when the key is not revoked.
Thialfihar