Remove some WebOb leftovers.

The deleted comments were talking about a swob EmptyResponse object,
which doesn't exist; it seems this was left over from the big WebOb
removal. Also, swob doesn't exhibit that behavior, so there's no point
in having this extra code path around.

Further, it seems like the hack was only needed with WebOb < 1.0.8. I
went back to Swift 1.4.8 (Essex) and compared it to master, and this
is the result:

DLO manifest HEAD
=================

Essex (ffadbc3)
---------------
Small #segments --> Content-Length: 12345
Large #segments --> Content-Length: 0
Large #segments sans shenanigans --> Content-Length: 0

master (f63b58f)
----------------
Small #segments --> Content-Length: 12345
Large #segments --> Content-Length: 0
Large #segments sans shenanigans --> Content-Length: 0

So, whatever WebOb wackiness this was intended to hack around, it
doesn't seem to have been here for a long, long time.

Change-Id: I7b717b1b36de1139cc5b76c166d1715dbc34b332
Add more stuff to SAIO doc's proxy pipeline.

If you're setting one of these up, you're probably going to use it for
development, in which case you want everything but the kitchen sink
turned on so you can just start hacking away.

Change-Id: I98d178ff545cbf8d853c102e9fce76fb9f6773ac
Merge "Add more stuff to SAIO doc's proxy pipeline."
Merge "Remove some WebOb leftovers."
catch OSError to prevent breaking request /recon/diskusage

swift.common.utils.ismount maybe raise some OSError in some special
cases; and the request against /recon/diskusage doesn't handle it
before. This patch let output of mounted keyword is the error's message.

Change-Id: I5d9018f580181e618a3fa072b7a760d41795d8eb
Closes-Bug: #1249181
Add swiftsync.

Change-Id: Ie588db762aedc55e00f8f51b3d2e329ba9a08a6c