Fix group_icon spec

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

spec/helpers/application_helper_spec.rb

@@ -52,7 +52,7 @@ describe ApplicationHelper do
     it "should give default avatar_icon when no avatar is present" do
       group = create(:group)
       group.save!
-      group_icon(group.path).to_s.should == "/assets/no_group_avatar.png"
+      group_icon(group.path).should match("group_avatar.png")
     end
   end