Configure mclag ports - b - #65

[vivek-metricdust]

backend fix for #65

Functionality which will suport the deletion of single member (Portchannel) of mclag if the member are provided it will delete only those portchannels else it will delete all the portchannels form members. Respective test cases are added to check the deletion of a single member and also delete all the members.

There is if statement in the mclag.py which will check

• if members is provided as key and with portchannel names as values it will remove only those portchannels.
• if member keys is provided with empty array it will remove all the members
• if there is no member key then it will delete the mclag

[vivek-metricdust]

All retested changes are added in commit fixes in 2691f44

New end point for deletion of member added. additional test cases to update the port channel member also added.