fix dracut dependencies

The "kpatch install" command is broken because the kpatch script has
some missing dependencies in the initramfs.  Make sure the new
dependencies (readelf and awk) are added to the initramfs.
change inst_symlink to inst for insmod

Use "inst" instead of "inst_symlink" for insmod, since insmod might not
necessarily be a symlink on some distros.  inst_symlink is functionally
the same as inst, with an additional check to make sure that it's a
symlink (which we don't care about either way).
Merge pull request #473 from jpoimboe/dracut-dependencies

fix dracut dependencies (and "kpatch install")