CVS migo: * fix a typo, so the old API is supported as intended

[FVWM CVS]

CVSROOT:        /home/cvs/fvwm
Module name:    fvwm
Changes by:     migo    09/03/18 14:26:50

Modified files:
        perllib        : ChangeLog 
        perllib/FVWM   : Module.pm.in 

Log message:
* fix a typo, so the old API is supported as intended