Modify the distcheck of POTFILES.skip to ignore scheme files

They need to be in the skip file to mollify newer intltool versions,
but still need to be handled by guile-strings.c for older versions of 
intltool.


git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/trunk@22836 57a11ea4-9604-0410-9ed3-97b8803252fd