Refactor bootstrap and run commands

1. Let's avoid bootstrapping kvm tests in powervm lpar
and if asked explicilty.

2. Adds a wrapper for running commands and exit incase
of failure.

3. Added independant package list based on environment,
that way we can avoid unwanted package install.

Signed-off-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>