Log Message:
Update to 1.3.8:

Serf 1.3.8 [2014-10-20, from /tags/1.3.8, rxxxx]
Fix issue #152: CRC calculation error for gzipped http reponses > 4GB.
Fix issue #153: SSPI CredHandle not freed when APR pool is destroyed.
Fix issue #154: Disable SSLv2 and SSLv3 as both or broken.