Log Message:
Update to 1.6.3

Changelog:
Changes for APR 1.6.3

  *) apr_file_trunc: Truncating a buffered file could add unexpected
     data after the truncate position. 51017.
     [Evgeny Kotkov <evgeny.kotkov visualsvn.com>]

  *) apr_file_trunc: Fix an issue where reading from a buffered file
     after truncate could return stale data from the buffer.
     [Evgeny Kotkov <evgeny.kotkov visualsvn.com>]

  *) apr_ipsubnet_create() now fails for an empty input string.
     [Joe Orton]