IDA Interface: ConvFit Throws Unhandled Exception

[mantid-builder]

Original Reporter: Michael Whitty

Reproduction steps:

1. Open IDA interface
2. Select ConvFit tab.
3. Use data files included in ticket http://trac.mantidproject.org/mantid/ticket/2904 as input.
4. Click "Run"

You would be present with a dialog:

Sorry, MantidPlot has caught an unexpected exception:

Convolution function is incomplete

Would you like to terminate MantidPlot or try to continue working?
If you choose to continue it is advisable to save your data and restart the application.
------------------------ - - - 
Terminate   Continue   
------------------------ - - - 

Though this is actually harmless, we should replace it with a more user-friendly error message.

[mantid-builder]

This issue was originally trac ticket 2911