mysys: Remove freebsd freopen implementation
mysys: Remove freebsd freopen implementation

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=79887
was fixed in 7.4 and 8.2.

Both of these reached end of life in February 2011
https://www.freebsd.org/releases/

Signed-off-by: Daniel Black <3d0f3b9ddcacec30c4008c5e030e6c13a478cb4f@linux.vnet.ibm.com>

natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2,natsys/mariadb_10.2