zebra_fpm: Add support for other protocols in fpm:netlink

zebra_fpm: Add support for other protocols in fpm:netlink

    fpm:netlink format doesn't indicate the protocol information
    in routes of BGP, OSPF and other protocols. Routes of those
    protocols just indicate protocol as zebra.

    The below route is actually BGP route but 'proto': 11
    indicates that it is zebra.

    {'attrs': [('RTA_DST', 'dummy'),
               ('RTA_PRIORITY', 0),
               ('RTA_GATEWAY', 'dummy'),
               ('RTA_OIF', 2)],
     'dst_len': 32,
     'family': 2,
     'flags': 0,
     'header': {'flags': 1025,
                'length': 60,
                'pid': 3160253895,
                'sequence_number': 0,
                'type': 24},
     'proto': 11,
     'scope': 0,
     'src_len': 0,
     'table': 254,
     'tos': 0,
     'type': 1}

    with this change it is now seen with 'proto': 186
    indicates that it is BGP.

    {'attrs': [('RTA_DST', 'dummy'),
               ('RTA_PRIORITY', 0),
               ('RTA_GATEWAY', 'dummy'),
               ('RTA_OIF', 2)],
     'dst_len': 32,
     'family': 2,
     'flags': 0,
     'header': {'flags': 1025,
                'length': 60,
                'pid': 3160253895,
                'sequence_number': 0,
                'type': 24},
     'proto': 186,
     'scope': 0,
     'src_len': 0,
     'table': 254,
     'tos': 0,
     'type': 1}

Signed-off-by: Spoorthi K <spk@redhat.com>