core:  [TEXT] restore.sh woes, unable to...

[TEXT] restore.sh woes, unable to restore engine DB without using -u postgres

1) removing the internal create/drop of the database, this should be
done manually as explained in the script usage statement
2) adding a comment that this script will work only for DB engine user
3) removing from backup script the -C flag to prevent database creation
statements generation
4) If an old backup having "CREATE DATABASE" or "ALTER DATABASE" is
used, those statements are removed before an attempt to restore the
database is done.

Change-Id: I44921d6fac57cfc565dacca52ed5a6d3b5b57f66
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=976337
Signed-off-by: Eli Mesika <emesika@redhat.com>