pgsql: Fix some jsonb issues found by Coverity in recent commits.

Fix some jsonb issues found by Coverity in recent commits.

Mostly these issues concern the non-use of function results. These
have been changed to use (void) pushJsonbValue(...) instead of assigning
the result to a variable that gets overwritten before it is used.

There is a larger issue that we should possibly examine the API for
pushJsonbValue(), so that instead of returning a value it modifies a
state argument. The current idiom is rather clumsy. However, changing
that requires quite a bit more work, so this change should do for the
moment.

Branch
------
master

Details
-------
http://git.postgresql.org/pg/commitdiff/c8315930e6a34b616d9840985c85eb0d856dd2df

Modified Files
--------------
src/backend/utils/adt/jsonb.c | 16 ++++++++--------
src/backend/utils/adt/jsonfuncs.c | 4 +++-
2 files changed, 11 insertions(+), 9 deletions(-)