qa: vstart wrapper helper for unittests

qa: vstart wrapper helper for unittests

Primarily useful to run scripts from qa/workunits as part of make check.

vstart_wrapper.sh starts a vstart.sh cluster, runs the command given in
argument and tearsdown cluster when it completes.

The vstart_wrapped_tests.sh script contains the list of scripts that
need the vstart_wrapper.sh to run. It would not be necessary if automake
allowed passing argument to tests scripts. It also adds markers to the
output to facilitate searching the output because it can be very verbose.

This wrapper is kept simple and will probably evolve into something more
sophisticated depending on the scripts being added to
vstart_wrapper_tests.sh. There are numerous options, ranging from
parsing the yaml from ceph-qa-suite to figure out the configuration
cluster to converting the same yaml into a puppet manifest that is
applied locally or even driving OpenStack instances to avoid messing
with the local machine. But this would probably be overkill at this
point.

Signed-off-by: Loic Dachary <loic@dachary.org>