Merge branch 'perf-thinlvhd-fixes' into 'master'

Merge branch 'perf-thinlvhd-fixes' into 'master'

Perf thinlvhd fixes

1- add fixes to the thin-lvhd performance tcs

2- add support for running thin-lvhd performance tcs on a lvmoiscsi SR backed by a physical netapp filer

3- extend resources.py ISCSIVMLun to allow the ISCSI VM to be backed by specific SRs in the host

4- add support for runninng the io latency thin-lvhd tc on a local lvmoiscsi supported by a local VM backed by a local SSD

5- add support for fio in the io latency thin-lvhd tc

NB: may need review by QA team due to (3) above.

See merge request !41