policycoreutils/setfiles: don't scramble stdout and stderr together

https://bugzilla.redhat.com/show_bug.cgi?id=1435894

When output to a non-tty (as caused by the implementation of fixfiles),
stdout is fully buffered.  stdout should be flushed before writes to
stderr.

See e.g. https://news.ycombinator.com/item?id=1271015

Signed-off-by: Alan Jenkins <alan.christopher.jenkins@gmail.com>

policycoreutils/setfiles/setfiles.c

@@ -149,6 +149,7 @@ log_callback(int type, const char *fmt, ...)
 		out = stdout;
 	} else {
 		out = stderr;
+		fflush(stdout);
 		fprintf(out, "%s: ", r_opts.progname);
 	}
 	va_start(ap, fmt);