fix check_snmp regex matches

the multiplier function always tried to extract a number, even if the result
is a string because of using a mib.

before:
```
./check_snmp -H hostname -P2c -c public -o IF-MIB::ifAdminStatus.11466 -vvv -r 0
/usr/bin/snmpget -Le -t 10 -r 5 -m ALL -v 2c [context] [authpriv] 10.0.13.11:161 IF-MIB::ifAdminStatus.11466
IF-MIB::ifAdminStatus.11466 = INTEGER: up(1)
Processing oid 1 (line 1)
  oidname: IF-MIB::ifAdminStatus.11466
  response:  = INTEGER: up(1)
SNMP OK - 0 | IF-MIB::ifAdminStatus.11466=0;;
```

the regexp 0 matches, even if the actual result is "up(1)".

after this patch:
```
./check_snmp -H hostname -P2c -c public -o IF-MIB::ifAdminStatus.11466 -vvv -r 0
/usr/bin/snmpget -Le -t 10 -r 5 -m ALL -v 2c [context] [authpriv] 10.0.13.11:161 IF-MIB::ifAdminStatus.11466
IF-MIB::ifAdminStatus.11466 = INTEGER: up(1)
Processing oid 1 (line 1)
  oidname: IF-MIB::ifAdminStatus.11466
  response:  = INTEGER: up(1)
SNMP CRITICAL - *up(1)* |
```

0 files changed, 0 insertions, 0 deletions