The issue was that clean_param took an int and returned a string
and the result was used in an exact comparison.
The type change mean the comparison failed.
The solution was to ensure the param was cast as a string.
It was not previously possible to have a section called 0 because of
bugs in the standard course formats, but we hit this with the OU course
format. You got an exception because backup settings tested to see if
their lable was empty, which means a section name of '0' was fatal.
Should work now.
* Root settings are now check boxes rather than selects
* Language strings adjusted as requested
* Final continue on backup now redirecteds to restore pre ui
* Category + course selectors now perform required capability checks
* Show/Hide settings from UI tested and implemented for overwrite_conf setting
* Final continue button is GET rather than post
* Temp zip file is deleted after successfull extraction
* Removed previous button from settings stage MDL-23480
