usertools: fix handling EOF for telemetry input pipe

usertools: fix handling EOF for telemetry input pipe

To allow the script to take queries from input pipes e.g. "echo
/ethdev/stats,0 | dpdk-telemetry.py", we need to handle the case of EOF
correctly without crashing with an exception. Do this by using a
try-except block around the input handling.

Fixes: 6a2967c112a3 ("usertools: add new telemetry script")
Cc: stable@dpdk.org
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Ciara Power <ciara.power@intel.com>