LU-11803 tests: don't assume obd device name

LU-11803 tests: don't assume obd device name

Several tests created to exercise lustre were developed on the
x86 platform and it was assumed the device name exposed in the
sysfs tree are the same across all platforms. Additionally
we can update the test to handle the case of using an uuid
format for the sysfs directory naming instead of an internal
address pointer.

Test-Parameters: clientdistro=ubuntu1804

Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Change-Id: I704d13059f76337fa49aab77f3e748a70a74f1bc
Reviewed-on: https://review.whamcloud.com/33894
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Nunez <jnunez@whamcloud.com>
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>