add portalias field in PORT_TABLE

[lguohan]

extend the port_config.ini format to have a port alias for each port. add a port alias field in the PORT_TABLE schema. populate port alias field in portsyncd.

This port alias will be used for by snmp subagent as the interface alias.

[lguohan]

port_config.ini current format:

# alias         lanes
Ethernet0       29,30,31,32
Ethernet4       25,26,27,28

port_config.ini future format. The alias can be optional, when there is no such field, then it won't appear in the port_table as well.

# name         lanes                alias
Ethernet0       29,30,31,32     fortyGigE0/0
Ethernet4       25,26,27,28     fortyGigE0/4

In the app db, port_tabel entry will has a new field/value.

127.0.0.1:6379> hgetall "PORT_TABLE:Ethernet0"
1) "lanes"
2) "29,30,31,32"
3) "admin_status"
4) "up"
5) "oper_status"
6) "up"
7) "mtu"
8) "1500"
9) "alias"
10) "fortyGigE0/0"

[stcheng]

resolved