pgsql: Fix a few places that were checking for the return value of

Log Message:
-----------
Fix a few places that were checking for the return value of palloc() to be
non-NULL: palloc() ereports on OOM, so we can safely assume it returns a
valid pointer.

Modified Files:
--------------
pgsql/contrib/chkpass:
chkpass.c (r1.14 -> r1.15)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/chkpass/chkpass.c.diff?r1=1.14&r2=1.15)
pgsql/contrib/fuzzystrmatch:
fuzzystrmatch.c (r1.19 -> r1.20)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/fuzzystrmatch/fuzzystrmatch.c.diff?r1=1.19&r2=1.20)
pgsql/src/backend/utils/adt:
cash.c (r1.66 -> r1.67)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/cash.c.diff?r1=1.66&r2=1.67)
pgsql/src/pl/plperl:
SPI.xs (r1.19 -> r1.20)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/SPI.xs.diff?r1=1.19&r2=1.20)
plperl.c (r1.106 -> r1.107)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/plperl.c.diff?r1=1.106&r2=1.107)