migrate_from_tempest.sh creates a commit for migrating code from
Tempest, but the commit message becomes long and redundant because
of containing file paths. Then now developers need to remove them
by hands.
This patch makes the script remove file paths.
In addition, this patch makes the script add the blueprint msg
"Partially implements blueprint migrate-service-clients-to-tempest-lib"
for managing these tasks on gerrit.
Change-Id: If8fc115dea67f779a86d33d26ac56cc8540a8c0f
59408c9253