test/unit.rb: initialize instance variable

* test/lib/test/unit.rb (Test::Unit::Parallel#non_options):
  initialize @jobserver instance variable to suppress warnings.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57524 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/lib/test/unit.rb

@@ -135,6 +135,7 @@ module Test
       end
 
       def non_options(files, options)
+        @jobserver = nil
         if !options[:parallel] and
           /(?:\A|\s)--jobserver-auth=(\d+),(\d+)/ =~ ENV["MAKEFLAGS"]
           begin