Replace service_helper with hosting class from the testlib.
Instead of invoking commands on remote via ssh_helper, we now use
shell from the hosting.
Signed-off-by: Vladimir Domnich <v.domnich@yadro.com>
Remove logic that checks for root login and prepends command with sudo, because
we should not use root login at all and all commands (that require higher permissions
should be prefixed with sudo anyways).
Add sudo prefix to privileged commands that require it.
Signed-off-by: Vladimir Domnich <v.domnich@yadro.com>
