cros_utils: fix a bad format string

`'%s' + 'bar' % baz` == `'%s' + ('bar' % baz)`, which raises an
exception. OTOH, `'%s' 'bar' % baz` == `('%s' 'bar') % baz`, so do that
instead.

BUG=None
TEST=Unittests

Change-Id: I83313e8fcb34d4ca923f3730133eec528ea6f9eb
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/2177144
Tested-by: George Burgess <gbiv@chromium.org>
Reviewed-by: Tiancong Wang <tcwang@google.com>
1 file changed