Slate: fix Propane placement in single-monitor layout
Slate: fix Propane placement in single-monitor layout

Whoops. Was accidentally sticking Propane on the right instead of on the
left.

Signed-off-by: Wincent Colaiuta <c76ac2e9cd86441713c7dfae92c451f3e6d17fdc@wincent.com>

wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent