More concise pipeline status titles

**app/mailers/emails/pipelines.rb:**

Make notification email subject more concise.

**app/views/notify/pipeline_failed_email.html.haml:**
**app/views/notify/pipeline_failed_email.text.erb:**
**app/views/notify/pipeline_fixed_email.html.haml:**
**app/views/notify/pipeline_fixed_email.text.erb:**
**app/views/notify/pipeline_success_email.html.haml:**
**app/views/notify/pipeline_success_email.text.erb:**

Make notification title more concise.

**spec/mailers/emails/pipelines_spec.rb:**
**spec/views/notify/pipeline_failed_email.html.haml_spec.rb:**
**spec/views/notify/pipeline_failed_email.text.erb_spec.rb:**
**spec/views/notify/pipeline_fixed_email.html.haml_spec.rb:**
**spec/views/notify/pipeline_fixed_email.text.erb_spec.rb:**
**spec/views/notify/pipeline_success_email.html.haml_spec.rb:**
**spec/views/notify/pipeline_success_email.text.erb_spec.rb:**

Update tests.