Add a missing include to JavaHL's jniwrapper.

* subversion/bindings/javahl/native/jniwrapper/jni_array.hpp:
   Include <cstring>.
  (Java::ByteArray::ByteArray): Qualify strlen in the ::std namespace.

* subversion/bindings/javahl/native/jniwrapper/jni_object.hpp:
   Include <cstring>.
  (Java::String::String): Qualify strlen in the ::std namespace.
  (Java::String::set_value): Likewise.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1539121 13f79535-47bb-0310-9956-ffa450edef68