eSATA auto mounting

[Phillip Susi]

Towards the end of last year, I tried to tackle the problem of udisks 
not automounting eSATA drives because it does not know they are external 
( and it doesn't auto mount internal drives ).  I ended up generating a 
patch for the kernel to read and report the ahci attribute bit flagging 
the port as external.  This patch ended up being ignored after several 
attempts to submit it upstream.

Now that I'm looking at it again, it occurs to me that this information 
should be reported in a more generic form rather than an ahci specific 
attribute.  What sysfs attribute does UDisks currently use for this?  I 
noticed that there is /sys/block/sda/removable, but this does not appear 
to be documented anywhere.