fix(sys-apps/efunctions): Fix INSTALL_MASK to remove init.d

When installing with the default make.conf in full effect
/etc/init.d/functions.sh will be excluded which is the whole point of
the efunctions package in the first place. This should fix that.
Merge pull request #31 from marineam/efunc

fix(sys-apps/efunctions): Fix INSTALL_MASK to remove init.d