findmissing: reduce spurious log

Print the "Finding" message only if it finds new rows.

BUG=b:223717399
TEST=./scripts/gce/full_sync_and_patch_create.sh

Change-Id: I01f086c656428d75d9e48707d7a920b9e12d7bff
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/dev-util/+/3949192
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Tested-by: Tzung-Bi Shih <tzungbi@chromium.org>
Commit-Queue: Tzung-Bi Shih <tzungbi@chromium.org>
diff --git a/contrib/findmissing/missing.py b/contrib/findmissing/missing.py
index bbb343e..2a2a8e1 100755
--- a/contrib/findmissing/missing.py
+++ b/contrib/findmissing/missing.py
@@ -517,8 +517,9 @@
             c.execute(q, [branch, branch])
             rows = c.fetchall()
 
-        logging.info('Finding new rows to insert into fixes table %s %s %s',
-                     chosen_table, chosen_fixes, branch)
+        if rows:
+            logging.info('Finding new rows to insert into fixes table %s %s %s',
+                         chosen_table, chosen_fixes, branch)
     except MySQLdb.Error as e: # pylint: disable=no-member
         logging.error('Error finding new rows to insert %s %s %s: error %d(%s)',
                       chosen_table, chosen_fixes, branch, e.args[0], e.args[1])