Fix typo in file name

MSP-11145
tools/missing-payload-tests.rb

MSP-11145

**NOTE: Failing specs**

Add a tool for reading `log/untested-payload.log` and
`framework.payloads` to determine `context`s to add
`spec/modules/payloads_spec.rb` to test the untested payloads.
Tag module specs with :content

MSP-11145

Tag content-related specs so they can be run separately in travis-ci.