Fix grub.conf if /boot is not a device

Fixes #24 using the approach suggested by @thouveng

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Ignore empty lines in /etc/sysconfig/network-scripts/ifcfg-*

Fixes #11

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
networkscripts: update test following interface change

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #35 from djs55/fix-install-wizard

Fix a number of install wizard glitches