libkmod-index: protect ourselves from corrupted indexes
libkmod-index: protect ourselves from corrupted indexes

If index is shorter than 12 bytes, we couldn't even read its header. Go
to error handling in this case.

pmmccorm/kmod,lpereira/kmod,pmmccorm/kmod,pmmccorm/kmod,Distrotech/kmod,Distrotech/kmod,lpereira/kmod,lucasdemarchi/kmod,lucasdemarchi/kmod,Distrotech/kmod,lpereira/kmod,lucasdemarchi/kmod