pgsql: Cosmetic code cleanup: fix a bunch of places that used "return

Log Message:
-----------
Cosmetic code cleanup: fix a bunch of places that used "return (expr);"
rather than "return expr;" -- the latter style is used in most of the
tree. I kept the parentheses when they were necessary or useful because
the return expression was complex.

Modified Files:
--------------
    pgsql/src/backend/access/heap:
        heapam.c (r1.205 -> r1.206)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/heap/heapam.c.diff?r1=1.205&r2=1.206)
        tuptoaster.c (r1.57 -> r1.58)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/heap/tuptoaster.c.diff?r1=1.57&r2=1.58)
    pgsql/src/backend/access/nbtree:
        nbtinsert.c (r1.129 -> r1.130)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/nbtree/nbtinsert.c.diff?r1=1.129&r2=1.130)
    pgsql/src/backend/access/transam:
        xlog.c (r1.225 -> r1.226)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xlog.c.diff?r1=1.225&r2=1.226)
        xlogutils.c (r1.39 -> r1.40)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/xlogutils.c.diff?r1=1.39&r2=1.40)
    pgsql/src/backend/executor:
        execMain.c (r1.263 -> r1.264)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/execMain.c.diff?r1=1.263&r2=1.264)
    pgsql/src/backend/libpq:
        be-secure.c (r1.60 -> r1.61)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/libpq/be-secure.c.diff?r1=1.60&r2=1.61)
    pgsql/src/backend/utils/adt:
        like.c (r1.62 -> r1.63)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/like.c.diff?r1=1.62&r2=1.63)
        mac.c (r1.35 -> r1.36)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/mac.c.diff?r1=1.35&r2=1.36)
        network.c (r1.57 -> r1.58)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/network.c.diff?r1=1.57&r2=1.58)
    pgsql/src/backend/utils/mb:
        encnames.c (r1.26 -> r1.27)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/mb/encnames.c.diff?r1=1.26&r2=1.27)
        mbutils.c (r1.53 -> r1.54)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/mb/mbutils.c.diff?r1=1.53&r2=1.54)
    pgsql/src/bin/psql:
        tab-complete.c (r1.143 -> r1.144)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/tab-complete.c.diff?r1=1.143&r2=1.144)
    pgsql/src/interfaces/libpq:
        fe-connect.c (r1.324 -> r1.325)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-connect.c.diff?r1=1.324&r2=1.325)
        fe-exec.c (r1.177 -> r1.178)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-exec.c.diff?r1=1.177&r2=1.178)
        fe-misc.c (r1.123 -> r1.124)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-misc.c.diff?r1=1.123&r2=1.124)
        fe-protocol2.c (r1.20 -> r1.21)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-protocol2.c.diff?r1=1.20&r2=1.21)
        fe-protocol3.c (r1.23 -> r1.24)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/libpq/fe-protocol3.c.diff?r1=1.23&r2=1.24)
    pgsql/src/tutorial:
        funcs.c (r1.12 -> r1.13)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/tutorial/funcs.c.diff?r1=1.12&r2=1.13)