Erase instances  if neutron tests fails
Erase instances  if neutron tests fails

Change-Id: I86a355fb8ff22fa4e97a86cb9d98e47e840160e4
Closes-Bug: #1456634

stackforge/fuel-ostf,eayunstack/fuel-ostf,eayunstack/fuel-ostf,stackforge/fuel-ostf,mcloudv/fuel-ostf,mcloudv/fuel-ostf