Update botan library.

Old version was 1.8.8, new one is 1.10.2.
We now put all the code into one pair of files (via
a botan configure option) and move platform-specific
defines into the pro/qbs files. Besides drastically
reducing the number of files, this is expected to make
future updates less messy.

Change-Id: I004166b2ab15b6a699d69aebfcfd9999c5ccdb91
Reviewed-by: hjk <qthjk@ovi.com>

src/libs/ssh/sshconnection_p.h

@@ -50,8 +50,6 @@ QT_BEGIN_NAMESPACE
 class QTcpSocket;
 QT_END_NAMESPACE
 
-namespace Botan { class Exception; }
-
 namespace QSsh {
 class SftpChannel;