Description:
------------
SNMP::setSecurity are wrong: it reports an extra 9th argument with no name.
See here for the commit in which it was introduced: https://github.com/php/php-src/commit/5e82e334ddffcf577542a74a37f3388d14790686#diff-6c46b817f999c7766e794fca1a93c68aR377

This extra argument does not seem to be used, not documented:

* https://github.com/php/php-src/blob/master/ext/snmp/snmp.c#L1908-L1909
* http://fr.php.net/manual/en/snmp.setsecurity.php

Test script:
---------------
reflection::export(new reflectionmethod('snmp', 'setSecurity'));

Expected result:
----------------
Method [ <internal:snmp> public method setSecurity ] {

  - Parameters [8] {
    Parameter #0 [ <required> $session ]
    Parameter #1 [ <required> $sec_level ]
    Parameter #2 [ <required> $auth_protocol ]
    Parameter #3 [ <required> $auth_passphrase ]
    Parameter #4 [ <required> $priv_protocol ]
    Parameter #5 [ <required> $priv_passphrase ]
    Parameter #6 [ <required> $contextName ]
    Parameter #7 [ <required> $contextEngineID ]
  }
}

Actual result:
--------------
Method [ <internal:snmp> public method setSecurity ] {

  - Parameters [9] {
    Parameter #0 [ <required> $session ]
    Parameter #1 [ <required> $sec_level ]
    Parameter #2 [ <required> $auth_protocol ]
    Parameter #3 [ <required> $auth_passphrase ]
    Parameter #4 [ <required> $priv_protocol ]
    Parameter #5 [ <required> $priv_passphrase ]
    Parameter #6 [ <required> $contextName ]
    Parameter #7 [ <required> $contextEngineID ]
    Parameter #8 [ <optional> $ ]
  }
}