FIx release packages to work with OS X 10.10 (Yosemite)

* tools/dist/release.py: Bump libtool version to 2.4.3, versions prior to 2.4.3
    treat OS X 10.10 as 10.1 which then causes the linker to be told to ignore
    undefined symbols rather than resolve them.  This causes runtime crashes.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1636714 13f79535-47bb-0310-9956-ffa450edef68