Ticket 205 - snmp counters index strings for multiple network interfaces with ip addr and tcp port pairs
    
    Bug Description:
    
    	When a host contains several interfaces, if several DS instances listen on the same port (but
    	on different interfaces) the snmp report will only contain one of those instances.
    
    Fix Description:
    
    	The fix is to define a new cn=config attribute (nsslapd-snmp-index) that is a number.
    	The value of this attribute will replace the instance port number (nsslapd-port) in the
    	snmp report.
    
    https://fedorahosted.org/389/ticket/205
    
    Reviewed by: Nathan Kinder (thanks Nathan)
    
    Platforms tested: Fedora 17
    
    Flag Day: no
    
    Doc impact: yes. A new configuration attribute (in cn=config) needs to be described ("nsslapd-snmp-index").
    	nsslapd-snmp-index: It specifies an index (identifier) that would be appened to the RHDS MIB OIDs of the instance.
    	If it is defined it will replace in the reported OID the 'port' (nsslapd-port).
    	For example:
    		instance1 and instance2 have defined nsslapd-snmp-index (greater than 0).
    		instance3 did not define nsslapd-snmp-index or nsslapd-snmp-index=0, so its slot number is appened.
    
    		> snmpwalk -v 2c -c redhat localhost RHDS-MIB::dsSimpleAuthBinds
    		RHDS-MIB::dsSimpleAuthBinds.<snmp_index_instance1> = Counter64: 16
    		RHDS-MIB::dsSimpleAuthBinds.<snmp_index_instance2> = Counter64: 4
    		RHDS-MIB::dsSimpleAuthBinds.<port_instance3> = Counter64: 24
    
    	In case of several RHDS instances listening on the same port (on different interfaces), it offers a means to link the reported snmp counters to a given instance.
    	This attribute is an optional numeric value greater or equal to 0.
    	0 means that the snmp index is not used and the SNMP report will contain the port number.
    	Any change of value requires (to be taken into account) restart of both DS and DS snmp sub-agent.