Description of problem:
When booting into rescue mode (linux rescue) from boot.iso,
once one gets to the system prompt and tries to execute 
'grub-install --root-directory=/mnt/sysimage /dev/sda'
it returns with a failure of 'can't find /sbin/grub' or 
'/sbin/grub not found', or some such.


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

How reproducible:
Always

Steps to Reproduce:
1. boot system into rescue mode (linux rescue from boot.iso prompt)
2. once to system prompt, enter 'grub-install --root-directory=/mnt/sysimage
/dev/sda'
3. 
  
Actual results:
/sbin/grub not found


Expected results:
grub-install fixes/sets up MBR for grub

Additional info:
If one symlinks /usr/sbin/grub to /sbin/grub, the above works.
So, either the path in grub-install needs to be changed to
/usr/sbin/grub, or $PWD/grub, or a symlink from /usr/sbin/grub to /sbin/grub
must be added, or the hard-path shouldn't be wired and let the PATH variable
resolve it.