kmod-depmod: fix comparison of module priority.
kmod-depmod: fix comparison of module priority.

This code was never tested, my bad!

 * the prefix should be ignored, as it is not stored in cfg_search/override.

 * baselen should not include '/'.

 * search length should not include '\0'.

 * override path should not include cfg->dirname prefix.

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