fix "svnadmin create" fail on x86

fix "svnadmin create" fail on x86

When run the following command on x86:

        svnadmin create /var/test_repo

It cause segmentation fault error like the following:

        [16499.751837] svnadmin[21117]: segfault at 83 ip 00000000f74bf7f6 sp 00000000ffdd9b34 error 4 in libc-2.24.so[f7441000+1af000]
        Segmentation fault (core dumped)

This is because in source code ./subversion/libsvn_fs_fs/low_level.c,
function svn_fs_fs__unparse_footer, when:

        target arch:    x86
        apr_off_t:      4 bytes

if the "APR_OFF_T_FMT" is "lld", it still use type "apr_off_t" to pass
data to apr, but in apr source code file apr_snprintf.c the function
apr_vformatter meet "lld", it would use the:

        i_quad = va_arg(ap, apr_int64_t);

It uses the apr_int64_t to deal data, it read 8 bytes, so the follow-up
data may be error.

Signed-off-by: Dengke Du <dengke.du@windriver.com>