set AWS_BUCKET just in one spec file

spec/jobs/match_appearance_releases_job_spec.rb

@@ -5,6 +5,10 @@ describe MatchAppearanceReleasesJob do
   let(:dummy_appearance_release) { create(:appearance_release_import, :with_headshot, :with_contract) }
   let(:dummy_matching_request) { instance_double(MatchingRequest, id: 999) }
 
+  before :all do
+    ENV["AWS_BUCKET"] = ""
+  end
+
   describe ".perform_now" do
     it "returns if no attachment is sent" do
       expect(MatchingRequest).not_to receive(:create)