pgsql: When using C-string lookup keys in a dynahash.c hash table, use

Log Message:
-----------
When using C-string lookup keys in a dynahash.c hash table, use strncpy()
not memcpy() to copy the offered key into the hash table during HASH_ENTER.
This avoids possible core dump if the passed key is located very near the
end of memory.  Per report from Stefan Kaltenbrunner.

Modified Files:
--------------
    pgsql/src/backend/utils/hash:
        dynahash.c (r1.61 -> r1.62)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/hash/dynahash.c.diff?r1=1.61&r2=1.62)
    pgsql/src/include/utils:
        hsearch.h (r1.37 -> r1.38)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/hsearch.h.diff?r1=1.37&r2=1.38)