Don't attempt to override a `set` with a `let`

spec/models/ci/build_spec.rb

@@ -679,21 +679,21 @@ describe Ci::Build do
 
         describe '#erase' do
           before do
-            build.erase(erased_by: user)
+            build.erase(erased_by: erased_by)
           end
 
           context 'erased by user' do
-            let!(:user) { create(:user, username: 'eraser') }
+            let!(:erased_by) { create(:user, username: 'eraser') }
 
             include_examples 'erasable'
 
             it 'records user who erased a build' do
-              expect(build.erased_by).to eq user
+              expect(build.erased_by).to eq erased_by
             end
           end
 
           context 'erased by system' do
-            let(:user) { nil }
+            let(:erased_by) { nil }
 
             include_examples 'erasable'
 
@@ -748,21 +748,21 @@ describe Ci::Build do
 
           describe '#erase' do
             before do
-              build.erase(erased_by: user)
+              build.erase(erased_by: erased_by)
             end
 
             context 'erased by user' do
-              let!(:user) { create(:user, username: 'eraser') }
+              let!(:erased_by) { create(:user, username: 'eraser') }
 
               include_examples 'erasable'
 
               it 'records user who erased a build' do
-                expect(build.erased_by).to eq user
+                expect(build.erased_by).to eq erased_by
               end
             end
 
             context 'erased by system' do
-              let(:user) { nil }
+              let(:erased_by) { nil }
 
               include_examples 'erasable'