[refpolicy] Fix typo in /etc/selinux/*/contexts/sepgsql_contexts

[Kohei KaiGai]

I found my typo in the sepgsql_contexts file.

In the initial setting up of SE-PostgreSQL, it alerts on an invalid
object type db_blobs,
however, it should be "db_blob", not "db_blobs".
Please apply this fix.

(Please ignore warnings about db_language. It is not a problem of
refpolicy side.)

[kaigai at vmlinux ~]$ postgres --single -F -O -c exit_on_error=true postgres \
        < /usr/local/pgsql/share/contrib/sepgsql.sql > /dev/null
/etc/selinux/targeted/contexts/sepgsql_contexts:  line 33 has invalid
object type db_blobs
/etc/selinux/targeted/contexts/sepgsql_contexts:  line 36 has invalid
object type db_language
/etc/selinux/targeted/contexts/sepgsql_contexts:  line 37 has invalid
object type db_language
/etc/selinux/targeted/contexts/sepgsql_contexts:  line 38 has invalid
object type db_language
/etc/selinux/targeted/contexts/sepgsql_contexts:  line 39 has invalid
object type db_language
/etc/selinux/targeted/contexts/sepgsql_contexts:  line 40 has invalid
object type db_language

Thanks,
-- 
KaiGai Kohei <kaigai at kaigai.gr.jp>