vmdk: Allow selecting SCSI adapter in image creation

Introduce a new option "adapter_type" when converting to vmdk images.
It can be one of the following: ide (default), buslogic, lsilogic
or legacyESX (according to the vmdk spec from vmware).

In case of a non-ide adapter, heads is set to 255 instead of the 16.
The latter is used for "ide".

Also see LP#545089

Signed-off-by: Othmar Pasteka <pasteka@kabsi.at>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/include/block/block_int.h b/include/block/block_int.h
index f7279b9..eaad53e 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -56,6 +56,7 @@
 #define BLOCK_OPT_SUBFMT            "subformat"
 #define BLOCK_OPT_COMPAT_LEVEL      "compat"
 #define BLOCK_OPT_LAZY_REFCOUNTS    "lazy_refcounts"
+#define BLOCK_OPT_ADAPTER_TYPE      "adapter_type"
 
 typedef struct BdrvTrackedRequest BdrvTrackedRequest;