Remove `TRAVIS_REPO_SLUG` variable. (#67587)

.travis.yml

@@ -46,7 +46,7 @@ install:
     mkdir -p "${TAP_DIR}"
     rsync -az --delete "${TRAVIS_BUILD_DIR}/" "${TAP_DIR}/"
     export TRAVIS_BUILD_DIR="${TAP_DIR}"
-    builtin cd "${TRAVIS_BUILD_DIR}"
+    builtin cd "${TAP_DIR}"
 
 script: brew cask ci
 

cmd/brewcask-ci.rb

@@ -151,11 +151,7 @@ module Cask
       end
 
       def tap
-        @tap ||= if ENV.key?("TRAVIS_REPO_SLUG")
-          Tap.fetch(ENV["TRAVIS_REPO_SLUG"])
-        else
-          Tap.from_path(Dir.pwd)
-        end
+        @tap ||= Tap.from_path(Dir.pwd)
       end
 
       def modified_files