In _ironic-conductor-pxe-init.sh.tpl file,
there are only codes for ubuntu system.
However in Openstack-Helm especially in kolla image,
there are Ubuntu version and CentOS version.
So add codes for OS dependency check and ipxe file PATH for each OS.
Change-Id: I04886da64ae0dfda782bcd8d8d2cde960ab1db1d
Signed-off-by: TaewooLee <tw0410.lee@samsung.com>