Remove bash/lsof dependencies from scripts

The wsrep_ scripts contain a number of unneccessary bashisms and needlessly require non-base packages on FreeBSD (lsof, bash).

I've created a pull-request for this that removes some of the bashisms, uses the POSIX compat mode of bash or another POSIX compatible shell that is found in "/bin/sh" on any system.

• Non-POSIX "${var}" == "value" -> POSIX "${var}" = "value"
• Don't use arrays

• split using ## and %%
• Use alternative quotes for the FILTERS list

The `wsrep_sst_rsync.sh` script uses `lsof` to find an rsync instance that listens on the configured port. On platforms with BSD netstat that can be accomplished with netstat from the base system. Currently this checks for $OS = FreeBSD but this should work on other BSD's as well.