Remove extra parameter breaking tests

[andrjohns]

Submission Checklist

• Run unit tests
• Declare copyright holder and agree to license (see below)

Summary

The R-devel tests are currently failing with a grepl error:

Error in grepl(as.character(pattern), x, ignore.case, FALSE, perl, fixed,  : 
  NA in coercion to boolean

It looks like this is caused by a couple of the expect_match calls accidentally including the input variable twice:

expect_match(out[1], " variable", out[1])

The second out[1] is assumed to be a boolean argument and R tries to convert it. I think it's only started to error recently since they've been majorly reworking the handling of boolean types in R's C API (but that's just a guess)

Copyright and Licensing

Please list the copyright holder for the work you are submitting
(this will be you or your assignee, such as a university or company):
Andrew Johnson

By submitting this pull request, the copyright holder is agreeing to
license the submitted work under the following licenses:

• Code: BSD 3-clause (https://opensource.org/licenses/BSD-3-Clause)
• Documentation: CC-BY 4.0 (https://creativecommons.org/licenses/by/4.0/)

[jgabry]

Looks good! will go ahead and merge.