floss_patches land: Avoid redundant newlines when description is empty BUG=b:361231905 TEST=floss_patches land --cl_number 3298391, https://crrev.com/c/5914037 Change-Id: I16f155bd80e472b7e5d582cffe12c721b57c5257 Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/bluetooth/+/5915433 Commit-Queue: Hsin-chen Chuang <[email protected]> Reviewed-by: Dean Liao <[email protected]> Tested-by: Hsin-chen Chuang <[email protected]>