improved app description and adjust it to the way the new encryption module works

apps/encryption/appinfo/info.xml

@@ -2,19 +2,14 @@
 <info>
 	<id>encryption</id>
 	<description>
-		This application encrypts all files accessed by ownCloud at rest,
-		wherever they are stored. As an example, with this application
-		enabled, external cloud based Amazon S3 storage will be encrypted,
-		protecting this data on storage outside of the control of the Admin.
-		When this application is enabled for the first time, all files are
-		encrypted as users log in and are prompted for their password. The
-		recommended recovery key option enables recovery of files in case
-		the key is lost.
-		Note that this app encrypts all files that are touched by ownCloud,
-		so external storage providers and applications such as SharePoint
-		will see new files encrypted when they are accessed. Encryption is
-		based on AES 128 or 256 bit keys. More information is available in
-		the Encryption documentation
+		In order to use this encryption module you need to enable server-side
+		encryption in the admin settings. Once enabled this module will encrypt
+		all your files transparently. The encryption is based on AES 256 keys.
+		The module won't touch existing files, only new files will be encrypted
+		after server-side encryption was enabled. It is also not possible to
+		disable the encryption again and switch back to a unencrypted system.
+		Please read the documentation to know all implications before you decide
+		to enable server-side encryption.
 	</description>
 	<name>Default encryption module</name>
 	<license>AGPL</license>