dracut.sh: always copy prelink files in FIPS mode

regardless of the the prelink={yes|no} switch
plymouth: also find the pkglibdir on debian
dracut-functions.sh: speed up ldconfig_paths()
Installing an OS with VLAN enabled to an ISCSI LUN (from ibft)

When installing OS to a VLAN enabled iscsi LUN (extracted from iBFT), "/tmp/net.{xyz}.has_ibft_config" is not being set properly.

Then anaconda installer requires 'BOOTPROTO="ibft"' populated in ifcfg of the vlan interface (ex: ibft0.20), for it to properly populate the kernel parameters post installation. The setting 'BOOTPROTO="ibft"' is populated by write-ifcfg.sh script only if the corresponding interface has a file /tmp/net.{xyz}.has_inft_config

To get around this issue, in ibft_to_cmdline() function in net-lib.sh file, I made the following changes to populate the has_ibft_config file for the vlan interface(ex: ibft0.20):