NEWS: mention improvements on instance allocation

This patch mentions the improvements of the iallocator
with respect to instance allocation of non-LVM disk
templates.
Signed-off-by: Helga Velroyen <helgav@google.com>
Reviewed-by: Klaus Aehlig <aehlig@google.com>

NEWS

@@ -14,6 +14,9 @@ Incompatible/important changes
   default. Specify --no-wait-for-sync to override this behavior.
 - The Ganeti python code now adheres to a private-module layout. In particular,
   the module 'ganeti' is no longer in the python search path.
+- On instance allocation, the iallocator now considers non-LVM storage
+  properly. In particular, actual file storage space information is used
+  when allocating space for a file/sharedfile instance. 
 
 New features
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