revert HPUX change since it already works fine

CHANGES

@@ -6,9 +6,6 @@
 
                                   Changelog
 
-Daniel Stenberg (23 Sep 2009)
-- HPUX does need _REENTRANT too to build really thread-safe.
-
 Daniel Stenberg (16 Sep 2009)
 - Sven Anders reported that we introduced a cert verfication flaw for OpenSSL-
   powered libcurl in 7.19.6. If there was a X509v3 Subject Alternative Name

RELEASE-NOTES

@@ -29,7 +29,6 @@ This release includes the following bugfixes:
  o improved NSS detection in configure
  o cookie expiry date at 1970-jan-1 00:00:00
  o libcurl-OpenSSL failed to verify some certs with Subject Alternative Name
- o builds thread-safer on HPUX
 
 This release includes the following known bugs:
 

m4/curl-reentrant.m4

@@ -5,7 +5,7 @@
 #                            | (__| |_| |  _ <| |___
 #                             \___|\___/|_| \_\_____|
 #
-# Copyright (C) 1998 - 2009, Daniel Stenberg, <daniel@haxx.se>, et al.
+# Copyright (C) 1998 - 2008, Daniel Stenberg, <daniel@haxx.se>, et al.
 #
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution. The terms
@@ -377,7 +377,7 @@ dnl Internal macro for CURL_CONFIGURE_REENTRANT.
 
 AC_DEFUN([CURL_CHECK_NEED_REENTRANT_SYSTEM], [
   case $host in
-    *-*-solaris* | *-*-hpux*)
+    *-*-solaris*)
       tmp_need_reentrant="yes"
       ;;
     *)