Prevent Hatchet on forked PRs [changelog skip] (#966)

* Update travis conditional for hatchet to check for HEROKU_API_ env vars
[changelog skip]

* remove check to skip hatchet in travis in favor of better travis config

.travis.yml

@@ -24,7 +24,7 @@ jobs:
     sudo: false
     script: make check
   - stage: Hatchet Integration
-    if: branch = master
+    if: env(TRAVIS_PULL_REQUEST_SLUG) = env(TRAVIS_REPO_SLUG)
     name: Run Hatchet
     script:
       - bundle exec hatchet ci:setup

spec/spec_helper.rb

@@ -15,16 +15,6 @@ RSpec.configure do |config|
   end
 end
 
-if ENV['TRAVIS']
-  # Don't execute tests against "merge" commits
-  if ENV['TRAVIS_PULL_REQUEST'] != 'false' &&
-      ENV['TRAVIS_BRANCH'] == 'master' &&
-      ENV["TRAVIS_PULL_REQUEST_SLUG"] != ENV['TRAVIS_REPO_SLUG'] # forked PR
-    puts "Skipping Hatchet tests"
-    exit 0
-  end
-end
-
 DEFAULT_STACK = 'heroku-18'
 
 def run!(cmd)