qa: recursively remove .gcno and .gcda

Instead of removing them only in the current directory. Leftovers
prevent running make check-coverage properly because lcov fails
when stumbling on old .gcno files with

lcov -d . -c -i -o check-coverage_base_full.lcov
Processing os/BtrfsFileStoreBackend.gcno
geninfo: ERROR: ceph/src/os/BtrfsFileStoreBackend.gcno: reached
         unexpected end of file

Signed-off-by: Loic Dachary <loic@dachary.org>
vstart/stop: use pkill instead of killall

killall fails to kill all OSDs when called as a oneliner. Replace with a
loop using pkill that retries until there are no more process to kill by
the required name.

Signed-off-by: Loic Dachary <loic@dachary.org>
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>
qa: add ../qa/workunits/cephtool/test.sh to unittests

Signed-off-by: Loic Dachary <loic@dachary.org>
Merge pull request #953 from dachary/wip-qa-suite

use qa/workunits/cephtool/test.sh as a unittest

Reviewed-by: Sage Weil <sage@inktank.com>