pgsql: Fix cases of discarding result from list API functions

Fix cases of discarding result from list API functions

Two cases violated list APIs by throwing away the return value. While
the code was technically correct, it relied on internal knowledge of
the list implementation, and the code wasn't really gaining anything
that way. It is planned to make this a compiler warning in the
future, so just fix these cases by assigning the return value
properly.

Reviewed-by: Michael Paquier <michael(at)paquier(dot)xyz>
Discussion: https://www.postgresql.org/message-id/flat/e3753562-99cd-b65f-5aca-687dfd1ec2fc(at)2ndquadrant(dot)com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/c77f6f50e4187bed38d1d36ae16b0c248e286d15

Modified Files
--------------
src/backend/commands/lockcmds.c | 2 +-
src/backend/parser/analyze.c | 3 +--
2 files changed, 2 insertions(+), 3 deletions(-)