pgsql: Remove more extraneous parentheses in date/time functions.

Log Message:
-----------
Remove more extraneous parentheses in date/time functions.

Modified Files:
--------------
pgsql/src/backend/utils/adt:
date.c (r1.107 -> r1.108)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/date.c.diff?r1=1.107&r2=1.108)
datetime.c (r1.143 -> r1.144)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/datetime.c.diff?r1=1.143&r2=1.144)
nabstime.c (r1.130 -> r1.131)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/nabstime.c.diff?r1=1.130&r2=1.131)
timestamp.c (r1.122 -> r1.123)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/timestamp.c.diff?r1=1.122&r2=1.123)
pgsql/src/interfaces/ecpg/pgtypeslib:
datetime.c (r1.21 -> r1.22)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/pgtypeslib/datetime.c.diff?r1=1.21&r2=1.22)
dt_common.c (r1.22 -> r1.23)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/pgtypeslib/dt_common.c.diff?r1=1.22&r2=1.23)
interval.c (r1.15 -> r1.16)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/pgtypeslib/interval.c.diff?r1=1.15&r2=1.16)
numeric.c (r1.20 -> r1.21)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/pgtypeslib/numeric.c.diff?r1=1.20&r2=1.21)
timestamp.c (r1.25 -> r1.26)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/pgtypeslib/timestamp.c.diff?r1=1.25&r2=1.26)