Check for the linux_distribution in the specific nodes

In the recent enhancement of upgrade kerenel task, the check for linux distribution
is added in the upgrade_kernel_all task, to decide precise/trusty. This check should be
done with settings as the sepcific nodes and not in the build machine.

Change-Id: Ibb2b0890ba4e49c87a5349c80d5871dbbfad39bc