Revert "Merge branch 'bvl-rename-build-events-to-job-events' into 'master'"

The migration fails with:

PG::NotNullViolation: ERROR:  column "job_events" contains null values
: ALTER TABLE "services" ADD "job_events" boolean NOT NULL/Users/mike/.rvm/gems/ruby-2.3.3/gems/activerecord-4.2.8/lib/active_record/connection_adapters/postgresql/database_statements.rb:155:in `async_exec'

Because rename_column_concurrently tries to create a new column with NULL without setting a default.

/cc @yorickpeterse