build-arm.sh: remove reference to docker.log.

tools/build-arm.sh

@@ -87,8 +87,8 @@ EOF
 while true
 do
   sleep 20
-  # print last line of log output and free memory
-  $SSH "tail -n1 src/pandoc/docker.log && free -h | grep Mem"
+  # print free memory
+  free -h | grep Mem"
   # Check to see if the artifact has been produced
   $SSH "ls -l src/pandoc/linux/artifacts/DONE 2>/dev/null" && break
 done