Reload channel data after edit.

This PR fixes a problem noticed while testing the display of channel.
To Test:
 * Select an image e.g. dv
 * Go to the acquisition tab. Expand one channel
 * Go back to the General tab
 * Change the name of the channel you expanded and Save
 * Go back to the Acquisition tab
 * Expand the channel you just edited. The channel info should be displayed (This was the bug, info not displayed)