Removed unnecessary try/catch from catalog algors. Refs #8445.

- The try/catch is no longer needed as we should not use these algorithms as a means of checking whether a user is logged in. Instead we have enabled/disabled the appropriate menus in another ticket.
Removed methods that are no longer needed. Refs #8445.
Merge branch 'feature/8445_icat_refactor_algorithms' into develop. Refs #8445.

Conflicts:
	Code/Mantid/MantidQt/MantidWidgets/inc/MantidQtMantidWidgets/CatalogHelper.h