* lib/drb/extservm.rb (DRb::ExtServManager): don't use /bin/sh to
	  invoke service subprocess.  mark detach threads for clean up.

	* test/drb/drbtest.rb: clean up the service subprocess in teardown.

	* test/drb/test_drb.rb: set @service_name for teardown.

	* test/drb/test_drbunix.rb: ditto.

	* test/drb/test_drbssl.rb: ditto.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@35714 b2dd03c8-39d4-4d8f-98ff-823fe69b080e