Locally disable rspec warning of message expectations on nil object
Locally disable rspec warning of message expectations on nil object

I disable the warning only in the context of a single example where
the test deliberately sets the user to nil and set message
expectations on it.

The warnings were:
```
      when current user is nil
An expectation of :present? was set on nil. Called from /home/david2/LocalSupport/spec/controllers/volunteer_ops_controller_spec.rb:121:in `block (5 levels) in <top (required)>'. Use allow_message_expectations_on_nil to disable warnings.
An expectation of :organization was set on nil. Called from /home/david2/LocalSupport/spec/controllers/volunteer_ops_controller_spec.rb:122:in `block (5 levels) in <top (required)>'. Use allow_message_expectations_on_nil to disable warnings.
```

tansaku/LocalSupport,curlygirly/LocalSupport,SergiosLen/LocalSupport,SergiosLen/LocalSupport,curlygirly/LocalSupport,marianmosley/LocalSupport,marianmosley/LocalSupport,tansaku/LocalSupport,intfrr/LocalSupport,davidbebb/local_support,intfrr/LocalSupport,tansaku/LocalSupport,decareano/LocalSupport,SergiosLen/LocalSupport,ZmagoD/LocalSupport,Aleks4ndr/LocalSupport,marianmosley/LocalSupport,Aleks4ndr/LocalSupport,intfrr/LocalSupport,ZmagoD/LocalSupport,ZmagoD/LocalSupport,decareano/LocalSupport,Aleks4ndr/LocalSupport,dsbabbar/LocalSupport,curlygirly/LocalSupport,Aleks4ndr/LocalSupport,intfrr/LocalSupport,davidbebb/local_support,curlygirly/LocalSupport,SergiosLen/LocalSupport,dsbabbar/LocalSupport,decareano/LocalSupport,davidbebb/local_support,tansaku/LocalSupport,dsbabbar/LocalSupport,davidbebb/local_support,ZmagoD/LocalSupport,dsbabbar/LocalSupport