Small miscellaneus fixes (Part II)

Hi.

There another assorted fixes to the head branch.

1. Avoid useless pointer increment
(src/backend/utils/activity/pgstat_shmem.c)
The pointer *p, is used in creation dsa memory,
not p + MAXALIGN(pgstat_dsa_init_size()).

2. Discard result unused (src/backend/access/transam/xlogrecovery.c)
Some compilers raise warnings about discarding return from strtoul.

3. Fix dead code (src/bin/pg_dump/pg_dump.c)
tbinfo->relkind == RELKIND_MATVIEW is always true, so "INDEX"
is never hit.
Per Coverity.

4. Fix dead code (src/backend/utils/adt/formatting.c)
Np->sign == '+', is different than "!= '-'" and is different than "!= '+'"
So the else is never hit.
Per Coverity.

5. Use boolean operator with boolean operands
(b/src/backend/commands/tablecmds.c)

regards,
Ranier Vilela