This commit fixes problems with parsing ipv6 addresses given via
the wsrep_sst_receive_address and wsrep_node_address options.
Also, this commit removes extra lines in the configuration files
in the mtr test suites for Galera related to these parameters.
The following features have been added:
1) Automatic addition of the pf = ip6 option for socat
when it can be recognized by the format of the connection
address;
2) Automatically add or remove extra commas at the beginning
and at the end of sockopt, for example, sockopt='pf=ip6'
and sockopt=',pf=ip6' work equally well;
Also, due to interference in the code of the get_transfer()
function, I also refactored it and now:
3) encrypt = 4 is supported not only for xtrabackup-v2,
but also for mariabackup - this can help with migration
from Percona;
4) Improved setting of 'commonname' option for encrypt=3
and encrypt=4 modes;