add a try/catch block and a loop to handle the case when the nickname used to join the MUC is already taken.
add a try/catch block and a loop to handle the case when the nickname
used to join the MUC is already taken.

gardenia/jitsi-hammer,jitsi/jitsi-hammer,bhatvv/jitsi-hammer,bhatvv/jitsi-hammer,jitsi/jitsi-hammer,gardenia/jitsi-hammer