Don't backup information/performance_schema dbs for mysql

We don't need these backed up, and having them in the list leads to
an error due to not having show_compatibility_56 enabled

ROOT/DEBIAN/control

@@ -3,7 +3,7 @@ Priority: optional
 Section: otherosfs
 Maintainer: Chemistry COs <support@ch.cam.ac.uk>
 Architecture: all
-Version: 0.9-ch67
+Version: 0.9-ch68
 Depends: zfs-dkms, postgresql-9.5 | postgresql-9.4 , liblockfile-simple-perl, libdbi-perl, libjson-perl, libzfs-perl-chem, libnet-openssh-perl, libdbd-pg-perl, mbuffer, rsync, nfs-kernel-server, pv, libwww-curl-perl
 Description: a backup system using ZFS (repository 'backup-scheduler')
  Ported (well, mostly) from FreeBSD to a Sane OS.

ROOT/etc/chem-zfs-backup-server/zfs-rsync.d/mysql-dump-script

@@ -42,7 +42,7 @@ SQLDIR=/var/lib/mysql-files/
 mkdir -p \$SQLDIR
 chown mysql:mysql \$SQLDIR
 
-DBS=\$($MYSQL -NB -e \"show databases\")
+DBS=\$($MYSQL -NB -e \"show databases\" | grep -vw information_schema | grep -vw performance_schema)
 
 for DB in \$DBS; do
  DB_DIR=\$SQLDIR/\$DB