crosh-{dev,usb}: fix re-exec logic

The quoting was off on these tools leading to the error:
	./crosh-usb: 10: exec: ./crosh --usb: not found

BUG=None
TEST=`./crosh-dev` works (runs crosh in dev mode)
TEST=`./crosh-usb` works (runs crosh in usb mode)

Change-Id: I67fc809d96d45cefb89c1ed52722c689201bd761
Reviewed-on: https://chromium-review.googlesource.com/178936
Reviewed-by: Chris Masone <cmasone@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
2 files changed