icat external download file creation

[mantid-builder]

Original Reporter: Jay Rainey

This ticket is blocked by :

• TRAC8730

If the user attempts to download a file from the catalog and does not have access to the archives it's downloaded over HTTPS.

However, if an error occurs then the content of this is written to the name of the file the user tried to download.

This can be mis-leading and lead to problems. Especially if the user presses "Load" as the file is downloaded and then attempted to load into Mantid, which will not work.

As such, we should never create a file nor write to it if an error occurs on the IDS. Instead, we must output a valid error message to the user. (The contents of which were previously written to a file).

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Keywords: ICAT

[mantid-builder]

This issue was originally trac ticket 8727