thread_pthread.c: fix vps_pagesize

* thread_pthread.c (hpux_attr_getstackaddr): vps_pagesize is defaulted
  to 16 and in Kbytes.  [ruby-core:56863]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42728 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* 2013-08-30

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42729 b2dd03c8-39d4-4d8f-98ff-823fe69b080e