AMT drivers recently were removed from ironic,
but some unit tests for AMT driver in ironic-staging-drivers still try
to use AMT-specific exceptions from ironic package instead of from
ironic-staging-drivers.
This patch changes affected places to use those exceptions from
ironic_staging_drivers.common module.
Change-Id: I7982cd8043a0508df6e26b8ef75738b7d3a82ee7
Closes-Bug: #1651069