[monit] Update the process snmp command line.

Signed-off-by: Yong Zhao <[email protected]>

Author: yozhao101

dockers/docker-snmp/base_image_files/monit_snmp

@@ -7,5 +7,5 @@
 check program container_process_snmpd with path "/usr/bin/process_checker snmp snmpd /usr/sbin/snmpd"
     if status != 0 for 5 times within 5 cycles then alert
 
-check program container_process_snmp_subagent with path "/usr/bin/process_checker snmp snmp_subagent python3 -m sonic_ax_impl"
+check program container_process_snmp_subagent with path "/usr/bin/process_checker snmp snmp_subagent python3.6 -m sonic_ax_impl"
     if status != 0 for 5 times within 5 cycles then alert