tuna: Fix race in is_hardirq_handler

It is better to try accessing the fields catching exceptions, as just
checking if we have that key is not enough for, right after, that thread
having gone away and the populating of that dict entry not finding the
file on /proc/PID/.

Signed-off-by: Arnaldo Carvalho de Melo <acme@felicio.ghostprotocols.net>
1 file changed