[docker-snmp]: Modify log level of snmpd (#9734)

#### Why I did it
resolves #8779
snmpd writes the below error message in syslog :
snmp#snmpd[27]: truncating integer value > 32 bits
This message is written in syslog when the hrSystemUptime(1.3.6.1.2.1.25.1.1.0 / system uptime) or sysUpTime(1.3.6.1.2.1.1.3 network management portion or snmpd uptime) is queried when either of these counters overflow beyond 32 bit value. This happens the device uptime or snmpd uptime is more than 497 days.

#### How I did it
Reference: https://access.redhat.com/solutions/367093 and https://linux.die.net/man/1/snmpcmd

To avoid seeing this message if the counter grows, the snmpd error log level is changed to display  LOG_EMERG, LOG_ALERT, LOG_CRIT, and LOG_DEBUG.

Without this change, LOG_ERR and LOG_WARNING would also be logged in syslog.

#### How to verify it
On a device which is up for more than 497 days, modify supervisord.conf  with the change and restart snmp.
Query 1.3.6.1.2.1.1.3 and verify that log message is not seen.

dockers/docker-snmp/supervisord.conf

@@ -40,7 +40,7 @@ dependent_startup=true
 dependent_startup_wait_for=rsyslogd:running
 
 [program:snmpd]
-command=/usr/sbin/snmpd -f -LS4d -u Debian-snmp -g Debian-snmp -I -smux,mteTrigger,mteTriggerConf,ifTable,ifXTable,inetCidrRouteTable,ipCidrRouteTable,ip,disk_hw -p /run/snmpd.pid
+command=/usr/sbin/snmpd -f -LS0-2d -u Debian-snmp -g Debian-snmp -I -smux,mteTrigger,mteTriggerConf,ifTable,ifXTable,inetCidrRouteTable,ipCidrRouteTable,ip,disk_hw -p /run/snmpd.pid
 priority=3
 autostart=false
 autorestart=false