Add test for LUClusterVerifyDisks
Add test for LUClusterVerifyDisks

This LU only creates additional jobs as result, so this is a trivial
unit test.

Signed-off-by: Thomas Thrainer <98bdeac947eb8ca18146e9ce7f092788ec242cd1@google.com>
Reviewed-by: Guido Trotter <f62ca4d5358bdaeef0e50e57f9f7e231de63727e@google.com>

mbakke/ganeti,bitemyapp/ganeti,onponomarev/ganeti,andir/ganeti,bitemyapp/ganeti,andir/ganeti,grnet/snf-ganeti,apyrgio/ganeti,ganeti/ganeti,mbakke/ganeti,leshchevds/ganeti,apyrgio/snf-ganeti,grnet/snf-ganeti,ganeti-github-testing/ganeti-test-1,dimara/ganeti,yiannist/ganeti,andir/ganeti,yiannist/ganeti,apyrgio/ganeti,yiannist/ganeti,dimara/ganeti,ganeti/ganeti,ganeti-github-testing/ganeti-test-1,leshchevds/ganeti,leshchevds/ganeti,ganeti/ganeti,onponomarev/ganeti,apyrgio/snf-ganeti,mbakke/ganeti