samples: pktgen: fix to print when terminated normally

Currently, most pktgen samples print the execution result when the
program is terminated normally. However, sample03 doesn't work
appropriately.

This is results of samples:

    # DEV=eth0 DEST_IP=10.1.0.1 DST_MAC=00:11:22:33:44:55 ./pktgen_sample04_many_flows.sh -n 1
    Running... ctrl^C to stop
    Device: eth0@0
    Result: OK: 19(c5+d13) usec, 1 (60byte,0frags)
    51762pps 24Mb/sec (24845760bps) errors: 0

    # DEV=eth0 DEST_IP=10.1.0.1 DST_MAC=00:11:22:33:44:55 ./pktgen_sample03_burst_single_flow.sh -n 1
    Running... ctrl^C to stop

The reason why it doesn't print the execution result when the program is
terminated usually is that sample03 doesn't call the function which
prints the result, unlike other samples.

So, this commit solves this issue by calling the function before
termination. Also, this commit changes control_c function to
print_result to maintain consistency with other samples.

Signed-off-by: Juhee Kang <claudiajkang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

samples/pktgen/pktgen_sample03_burst_single_flow.sh

@@ -85,7 +85,7 @@ for ((thread = $F_THREAD; thread <= $L_THREAD; thread++)); do
 done
 
 # Run if user hits control-c
-function control_c() {
+function print_result() {
     # Print results
     for ((thread = $F_THREAD; thread <= $L_THREAD; thread++)); do
 	dev=${DEV}@${thread}
@@ -94,11 +94,13 @@ function control_c() {
     done
 }
 # trap keyboard interrupt (Ctrl-C)
-trap control_c SIGINT
+trap true SIGINT
 
 if [ -z "$APPEND" ]; then
     echo "Running... ctrl^C to stop" >&2
     pg_ctrl "start"
+
+    print_result
 else
     echo "Append mode: config done. Do more or use 'pg_ctrl start' to run"
 fi