xkbcomp currently emits

type[group1]="ONE_LEVEL",

instead of

type[Group1]="ONE_LEVEL",

so we would rather match both cases, and similary for other such
matching.

This notably fixes the shift+altgr+key combination: altgr was not
recognized as type ONE_LEVEL any more, and would thus make shift+altgr
interpreted as alt instead of ISO_Level3_Shift, while altgr+shift+key
was still working, thus confusing users a lot.