Anaconda iSCSI Cleanup

Summary

Improve anaconda's iSCSI support.

This is a complete iscsi rewrite that also adds the new libiscsi and associated python bindings.

iSCSI support in anaconda needed extensive cleanup. This feature replaces existing code with new code using libiscsi.

Fixes:

Report error when we cannot add a disk instead of silently failing (461830)
Report error when trying to use iscsi from kickstart without having an iscsiname directive first (463156)
Better feedback while scanning iscsi disks
Make ibft work with chap and 2-way chap
Make ibft configured disks available for upgrades and in rescue mode
Make ibft boot work even when iscsi-initiator-utils is installed after the kernel in the transaction

Fewer anaconda bugs and easier maintenance. Additional support for ibft, CHAP, reverse CHAP.

Test install to a regular disk with /home on iscsi using no authentication
Test install to a regular disk with /home on iscsi using 1-way CHAP
Test install to a regular disk with /home on iscsi using 2-way CHAP
Test install with / on iscsi using an iBFT capable system using no authentication
Test install with / on iscsi using an iBFT capable system using 1-way CHAP
Test install with / on iscsi using an iBFT capable system using 2-way CHAP
Test install with / on 1 iscsi target and /home on a different target using an iBFT capable system
Test install with / on 1 iscsi lun and /home on a different lun of the same target using an iBFT capable system

When using NetworkManager for network configuration and using an iscsi /, other iscsi based file systems (ie /boot) will not be brought up automatically.

None

None; this is a necessary revision of existing (broken) support

Not user visible so none needed