Avoid needlessly persisting to db in equipment model spec

Resolves #1665
-change spec to build_stubbed instead of build

spec/models/equipment_model_spec.rb

@@ -27,7 +27,6 @@ def mock_eq_model(**attrs)
     it { is_expected.to accept_nested_attributes_for(:checkout_procedures) }
     it { is_expected.to have_and_belong_to_many(:associated_equipment_models) }
     it { is_expected.to validate_presence_of(:name) }
-    it { is_expected.to validate_uniqueness_of(:name) }
     it { is_expected.to validate_presence_of(:description) }
     it { is_expected.to belong_to(:category) }
     it 'requires an associated category' do
@@ -36,6 +35,11 @@ def mock_eq_model(**attrs)
     end
   end
 
+  describe 'validations requiring peristance' do
+    subject { FactoryGirl.build(:equipment_model) }
+    it { is_expected.to validate_uniqueness_of(:name) }
+  end
+
   describe 'attribute-specific validations' do
     shared_examples 'integer attribute' do |attr|
       it 'is valid with an integer value' do