test/metrics: fix a negative case

test/metrics: fix a negative case

Negative test case for passing invalid count size to
rte_metrics_update_values() will pass if count value
is any value greater than 1 because set size wrt to
key id 1 is 1 and passing 0 as no of values to be
updated will not hit the ERANGE check.

Fixes: cd3804242901 ("test/metrics: add unit tests for metrics library")
Cc: stable@dpdk.org
Signed-off-by: Harman Kalra <hkalra@marvell.com>
Acked-by: Remy Horton <remy.horton@intel.com>