[pgpool-committers: 4800] pgpool: Fix memory leaks related to pool_extract_error_message().

[Tatsuo Ishii]

Fix memory leaks related to pool_extract_error_message().

After 3.4, the function starts to return palloc'ed memory, and the
caller should had been modified so that they pfree the memory returned
by it but actually they had not.

Branch
------
V3_7_STABLE

Details
-------
https://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=a50025bc1e4b6689bdc58e94ab9b80860e32ab3b

Modified Files
--------------
src/auth/pool_auth.c              | 15 ++++++++++++---
src/protocol/child.c              |  3 ++-
src/protocol/pool_process_query.c |  4 +++-
src/protocol/pool_proto_modules.c |  1 +
4 files changed, 18 insertions(+), 5 deletions(-)