ros_bag) failed save blocks future saves

[Garfonso]

If you try to save a region of a bag file and that fails (for example insufficient write rights in a directory) you get an error message. If you try to save again in a different folder, you get the message that says to wait for the previous save-operation to finish (which will obviously never happen).

To reproduce:

• try to save bag file somewhere without write rights
• dismiss error message
• try to save again

[ablasdel]

Thanks for the info. I'll take a look at this when I get a chance.