pgsql: Fix pg_dumpall so that when --clean is specified, it drops roles

Log Message:
-----------
Fix pg_dumpall so that when --clean is specified, it drops roles and
tablespaces in an order that has some chance of working.
Per a complaint from Kevin Bailey.

This is a pre-existing bug, but given the lack of prior complaints I'm
not sure it's worth back-patching.  In most cases failure of the DROP
commands wouldn't be that important anyway.

In passing, fix syntax errors in dumpCreateDB()'s queries for old servers;
these were apparently introduced in recent binary_upgrade patch.

Modified Files:
--------------
    pgsql/src/bin/pg_dump:
        pg_dumpall.c (r1.123 -> r1.124)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dumpall.c?r1=1.123&r2=1.124)