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]>
diff --git a/tools/floss_patches b/tools/floss_patches
index 4af05d7..a21911b 100755
--- a/tools/floss_patches
+++ b/tools/floss_patches
@@ -800,12 +800,17 @@
                 test += line + "\n"
             else:
                 description += line + "\n"
+
+    # If description is not empty, append a blank line to separate it from the
+    # following "cherry-pick ... " line.
+    description = description.strip()
+    if description:
+        description += "\n\n"
+
     cl_message = f"""\
 floss UPSTREAM: {subject}
 
-{description.strip()}
-
-(cherry-pick from https://r.android.com/{cl_number})
+{description}(cherry-pick from https://r.android.com/{cl_number})
 
 {bug.strip() or 'BUG=None'}
 {test.strip() or 'TEST=CQ'}