[fix][rqt_bag_plugins] 'image_helper' is not defined" error.

[130s]

Similar to #424, without this PR I get the following error when I click Toggle Thumbnail button after loading a .bag file that contains image topics.

$ rqt&
$ Loading /home/rosnoodle/Desktop/2017-01-30-15-03-19.bag
Done loading /home/rosnoodele/Desktop/2017-01-30-15-03-19.bag
Error loading image on topic /camera/image_raw: global name 'image_helper' is not defined
Disabling renderer on /camera/image_raw

$ rospack find rqt_bag
/home/rosnoodele/cws_viz/src/ros-visualization/rqt_common_plugins/rqt_bag
$ roscd rqt_bag
$ git log
commit 2c2487a02c83628a14be7bde318d20249167ffdb
Author: Dirk Thomas <dthomas@osrfoundation.org>
Date:   Tue Jan 31 12:35:55 2017 -0800

    fix bag_helper import
:

(For testing I used this bag file that contains images (500+MB though, and URL will likely change soon).

[130s]

Tested on Indigo - Python2 only. About to test on Kinetic now.

[dirk-thomas]

Reviewing the PR #421 which introduced the regressions it looks like this line needs the same fix:

rqt_common_plugins/rqt_bag_plugins/src/rqt_bag_plugins/image_view.py

Line 46 in 2c2487a

import rqt_bag_plugins.image_helper

Could you please update this PR to fix that line too.

[130s]

Ok, rqt_bag_plugins/image_view.py is changed too.

On my Kinetic I have a Qt issue that has nothing to with the issue here, so I'm not able to test this for now. If someone can test that'll be great.

[dirk-thomas]

Thanks for patch.

[130s]

Confirmed on Kinetic too that the issue raised is fixed with this PR.