BUG/MINOR: mux-h2: Fix possible null pointer deref on h2c in _h2_trace_header()

As reported by Coverity, this function may be called with no h2c. Thus, the
pointer must always be checked before any access. One test was missing in
TRACE_PRINTF_LOC().

This patch should fix the issue #2015. No backport needed, except if the
commit 11e8a8c2a ("MEDIUM: mux-h2/trace: add tracing support for headers")
is backported.
1 file changed