BUILD/MINOR: opentracing: fixed build when using clang

The arguments of the snprintf() function are now consistent with the
format used.

This should fix the github issue #1242.

(cherry picked from commit 65b86685e1bdc77bc2ea6c2ed888d1cf8ca8f484)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
1 file changed