support for case of unassigned ipv6 address as chassis ID

ntc_templates/templates/cisco_ios_show_lldp_neighbors_detail.textfsm

@@ -1,5 +1,5 @@
 Value LOCAL_INTERFACE (\S+)
-Value CHASSIS_ID ([^:]+)
+Value CHASSIS_ID (([^:]+|::))
 Value NEIGHBOR_PORT_ID (.*)
 Value NEIGHBOR_INTERFACE (.*)
 Value NEIGHBOR_NAME (.+?)

tests/cisco_ios/show_lldp_neighbors_detail/cisco_ios_show_lldp_neighbors_detail6.raw

@@ -0,0 +1,45 @@
+------------------------------------------------
+Local Intf: Gi1/0/22
+Chassis id: ::
+Port id: aabbccddeeff:P1
+Port Description: SW PORT
+System Name: SEPaabbccddeeff.phones.company.domain
+
+System Description:
+Cisco IP Phone 6901,SCCP6901.9-3-1-SR2-2
+
+Time remaining: 44 seconds
+System Capabilities: T
+Enabled Capabilities: T
+Management Addresses:
+    IP: 10.20.30.40
+    IPV6: ::
+Auto Negotiation - supported, enabled
+Physical media capabilities:
+    100base-TX(FD)
+    100base-TX(HD)
+    10base-T(FD)
+    10base-T(HD)
+Media Attachment Unit type: 16
+Vlan ID: 999
+Peer Source MAC: aabb.ccdd.eeff
+
+MED Information:
+
+    MED Codes:
+          (NP) Network Policy, (LI) Location Identification
+          (PS) Power Source Entity, (PD) Power Device
+          (IN) Inventory
+
+    H/W revision: 1.0
+    F/W revision: 6901.0-0-0-01-05
+    S/W revision: SCCP6901.9-3-1-SR2-2
+    Serial number: FCH12345GVM
+    Manufacturer: Cisco Systems, Inc.
+    Model: CP-6901
+    Capabilities: NP, PD, IN
+    Device type: Endpoint Class III
+    Network Policy(Voice): VLAN data, untagged, Layer-2 priority: 5, DSCP: 46
+    Network Policy(Voice Signal): VLAN data, untagged, Layer-2 priority: 3, DSCP: 46
+    PD device, Power source: Unknown, Power Priority: Unknown, Wattage: 2.6
+    Location - not advertised

tests/cisco_ios/show_lldp_neighbors_detail/cisco_ios_show_lldp_neighbors_detail6.yml

@@ -0,0 +1,24 @@
+---
+parsed_sample:
+  - capabilities: "T"
+    chassis_id: "::"
+    fw_revision: "6901.0-0-0-01-05"
+    hw_revision: "1.0"
+    local_interface: "Gi1/0/22"
+   mac_address: "aabb.ccdd.eeff"
+    manufacturer: "Cisco Systems, Inc."
+    mgmt_address: "10.20.30.40"
+    neighbor_description: "Cisco IP Phone 6901,SCCP6901.9-3-1-SR2-2"
+    neighbor_interface: "SW PORT"
+    neighbor_name: "SEPaabbccddeeff.phones.company.domain"
+    neighbor_port_id: "aabbccddeeff:P1"
+    platform: "CP-6901"
+    power_class: ""
+    power_device_type: ""
+    power_pair: ""
+    power_priority: ""
+    power_requested: ""
+    power_source: ""
+    serial: "FCH12345GVM"
+    sw_revision: "SCCP6901.9-3-1-SR2-2"
+    vlan_id: "999"