Fix a pool lifetime bug in JavaHL.

* subversion/bindings/javahl/native/org_apache_subversion_javahl_util_ConfigLib.cpp
  (SimpleSearchCallback): Build the Java representation of the credential within
   the callback itself, because that's where the pool from which the credentials
   hash was allocated is still valid.
  (Java_org_apache_subversion_javahl_util_ConfigLib_nativeGetCredential,
   Java_org_apache_subversion_javahl_util_ConfigLib_nativeRemoveCredential):
   Just return the credential from the callback instance.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1605739 13f79535-47bb-0310-9956-ffa450edef68