MFH: r476650

databases/xtrabackup: Revert depdendency removal

There is a perl script embedded in the binary which can be found at
storage/innobase/xtrabackup/src/version_check.pl. This script can be
ignored if you pass the argument --no-version-check. It could be
possible to replace this with a simple shell script to achieve the same
results and eliminate the dependency on a specific external
libmysqlclient library inherited from DBD::MySQL. This will be
investigated to eliminate this issue.

Pointyhat: me