If you have a path with special characters it may be easier to hand them to
swift-temp-url prequoted than try to escape them on the command line. By the
time common.middleware.tempurl gets ahold of the path it's unquoted so we do
the same before calculating the hmac but still use the pre-quoted path output
to the commandline.
Change-Id: Ia1a9666e487b1e70e4db7cd597bc6a1027e3e918
b7659bee26