fix shellcheck

sbin/run_integration_test.sh

@@ -140,7 +140,7 @@ function cleanup {
     done
 
     # clean up empty files (most containers log to either stderr or stdout)
-    find log -size 0 | xargs rm
+    find log -size 0 -exec rm {} ';'
   fi
   if [ -z "${preserve}" ]; then
     make stop > /dev/null 2>&1