Description of problem:

Discovery kexec is not working after upgrading Satellite to 6.4 with Nutanix Acropolis Hypervisors.

Version-Release number of selected component (if applicable): 6.4

How reproducible: Always

Steps to Reproduce:
1. Discover a host using the latest foreman-discovery image
2. Enable ssh on the host and run "journatl -f" on the host so that we can get the logs related to kexec
3. Go to "discovered hosts", fill up the form and hit submit

Actual results:

kexec does not get triggered properly and hence the system reboots.

Expected results:

kexec should get triggered and put the system into build mode.

Additional info:

Host logs shows that kexec gets initiated, but shows no errors:

19:21:42:38] "PUT /power/kexec HTTP/1.1" 200 15
Feb 16 21:42:39 fdi smart-proxy[1201]: - -> /power/kexec
Feb 16 21:42:39 fdi foreman-proxy[1201]: close: 192.168.1.189:54470 Feb 06 21:42:41 fdi foreman-proxy[1201]: Power API executing: ["/usr/sbin/kexec" , "--debug", "--force", "--reset-vga", "--append=ks=http://satellite.example.com/unattended/provision?token=f98bd1e4-4583-45f2-ba6d-3cdbe56d2cf6&static=yes inst.ks.sendmac ip=192.168.1.2::192.168.1.1:255.255.255.0:::none eserver=1.1.1.1 ksdevice=bootif BOOTIF=XX-XX-XX-XX-XX-XX-XX nomodeset ", "--initrd=/tmp/initrd.img", "/tmp/vmlinuz"]
Feb 16 21:42:41 fdi sudo[1487]: foreman-proxy : TTY=unknown ; PWD=/ ; USER=root ; COMMAND=/usr/sbin/kexec --debug --force --reset-vga --append=ks=http://satellite.example.com/unattended/provision?token=f98bd1e4-4583-45f2-ba6d-3cdbe56d2cf6&static=yes inst.ks.sendmac ip=192.168.1.2::192.168.1.1:255.255.255.0:::none nameserver=1.2.3.4 ksdevice=bootif BOOTIF=XX-XX-XX-XX-XX-XX-XX nomodeset --initrd=/tmp/initrd.img /tmp/vmlinuz
IF=XX-XX-XX-XX-XX-XX-XX nomodeset ","extra":[]}
Feb 06 21:42:39 fdi foreman-proxy[1201]: Downloading: http://satellite.example.com/pulp/repos/acmeinc/rhel7-standard/content/di