Backport r1593600 from 1.6:
Backport r1438940 from trunk:

    Don't leak memnodes in apr_pvsprintf() if out of memory and no pool abort
    function is set



git-svn-id: https://svn.apache.org/repos/asf/apr/apr/branches/1.5.x@1593610 13f79535-47bb-0310-9956-ffa450edef68