File not found message remains after Save As

[ntrel]

Steps to reproduce:

• open a file
• delete the file outside geany
• geany will notice and show the message banner
• Choose File->Save As and save the file with a different name
• the message remains

Tested on Linux, think I discovered it on Windows.

[Guiikcar]

I have reproduce the bug, and I have worked on that i did a pull request, i m new in free-software and i think i have resolve the bug (don't hesitate to give me some feedback/tell me if i do something bad i m here to learn) thanks you!

[ntrel]

Thanks - #3453