check_snmp: small improvement by anonymous submission

- response should not start with the delimiter
- OID response value taken into account

Closes issue monitoring-plugins#1029
Closes push request monitoring-plugins#1173

plugins/check_snmp.c

@@ -380,6 +380,7 @@ main (int argc, char **argv)
 		response = strstr (ptr, delimiter);
 		if (response == NULL)
 			break;
+		response = response + 3;
 
 		if (verbose > 2) {
 			printf("Processing oid %i (line %i)\n  oidname: %s\n  response: %s\n", i+1, line+1, oidname, response);
@@ -411,6 +412,9 @@ main (int argc, char **argv)
 		else if (strstr (response, "INTEGER: ")) {
 			show = strstr (response, "INTEGER: ") + 9;
 		}
+		else if (strstr (response, "OID: ")) {
+			show = strstr (response, "OID: ") + 5;
+		}
 		else if (strstr (response, "STRING: ")) {
 			show = strstr (response, "STRING: ") + 8;
 			conv = "%.10g";