follow up r62353 Make ApiBase::requireOnlyOneParameter() accept parameters that are...

follow up r62353 Make ApiBase::requireOnlyOneParameter() accept parameters that are set, but false.  This means that you can pass in more than one parameter, as long as it is the same as the default (false).  Have to do it this way since we'd like to default boolean parameters to false in getAllowedParams() but by the time requireOnlyOneParameter() is called, the defaults are set, so we can't tell the difference between passing in a parameter set to the default and just getting the defaults.