virttest.staging: Add lv_utils

As a recent patchset introduced a dependency on lv_utils,
now we have to replicate it to staging, so people using
the autotest 0.14 RPMs can still use the test suite.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
Merge pull request #1409 from autotest/lv_utils

virttest.staging: Add lv_utils