Remove command setting export header as generated.
Remove command setting export header as generated.

nickerso/libcellml,hsorby/libcellml,libcellml/buildbot-testing,nickerso/libcellml,MichaelClerx/libcellml,nickerso/libcellml,nickerso/libcellml,cellml/libcellml,MichaelClerx/libcellml,MichaelClerx/libcellml,libcellml/buildbot-testing,cellml/libcellml,hsorby/libcellml,cellml/libcellml,hsorby/libcellml,cellml/libcellml,hsorby/libcellml