pgsql: Avoid memcpy() with same source and destination address.

Avoid memcpy() with same source and destination address.

The behavior of that is undefined, although unlikely to lead to problems in
practice.

Found by running regression tests with Valgrind.

Branch
------
REL9_3_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/8332fe76b559dd7d0a689ec66e96c359e67e1f3b

Modified Files
--------------
src/backend/tsearch/dict_ispell.c |    9 ++++-----
src/backend/utils/adt/tsvector.c  |    3 ++-
2 files changed, 6 insertions(+), 6 deletions(-)