Fix ARM releases to be quantal armv7l releases.
Made grub execution conditional and not done when ARM.
Use ctx parameter to change machine type to tala.
Fix kernel assignments when running ARM systems.
Added workaround for uname -r bug.

Fixes: #5000
Signed-off-by: Warren Usui <warren.usui@inktank.com>
Changed ARM kernel code to use the uname -r result.  The value was not
getting set because a reboot was needed (now added).