[Backport #3474] SocketError on SnowLeopard (during make test-all)

Backport #3474: SocketError on SnowLeopard (during make test-all)
http://redmine.ruby-lang.org/issues/show/3474

e$B5/I<<Te(B: Wataru Kimura
e$B%9%F!<%?%9e(B: Open, e$BM%@hEYe(B: Normal

Bug #3124e$B$N=$@5$re(B1.8e$B$K$b<h$j9~$s$G$$$?$@$1$J$$$G$7$g$&$+!#e(B
r28401e$B$NJQ99$re(B1.8e$BMQ$K$7$?%Q%C%A$rE:IU$7$^$9!#e(B