Set default Digest Message to use SHA1 instead of MD5 in openssl tests
as MD5 signature are now rejected by newer openssl Version.

Noticed in RHEL-7 and Fedora 21 build.
Merge branch 'PHP-5.4' into PHP-5.5

* PHP-5.4:
  Set default Digest Message to use SHA1 instead of MD5 in openssl tests as MD5 signature are now rejected by newer openssl Version.