On the 1.7.x-md5-collision branch: Merge r1550691, r1550772, r1600909 from trunk.

svn_hash_gets(...) was changed to apr_hash_get(..., APR_HASH_KEY_STRING) since
the svn_hash_gets() macro was not available in 1.7.x.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.7.x-md5-collision@1600983 13f79535-47bb-0310-9956-ffa450edef68