When using pipes in ansible shell module we can miss the error
because shell is executing without pipefail by default.
This rule will check every shell module if it has "set -e pipefail"
and will fail in case if not.
It excludes tasks which have 'ignore_errors: true' or register
variables.
Change-Id: I394c72040d62dff76180aeb9d703bb8a212bcc98
