AES_CBC is now supported for binlog encryption

AES_CBC can be used for binlog files encryption

The AES_CBC could leaves some not handled bytes in the buffer and those
need a special encoding (ECB and XOR)

This way the output buffer of the whole encoding with AES_CBC will have
same size as the input (AES_CTR does it without any other step)

server/modules/routing/binlog/blr.h

@@ -83,7 +83,8 @@ MXS_BEGIN_DECLS
 enum blr_aes_mode
 {
     BLR_AES_CBC,
-    BLR_AES_CTR
+    BLR_AES_CTR,
+    BLR_AES_ECB
 };
 
 /* Default encryption alogorithm is AES_CTR */