[pgpool-committers: 1691] pgpool: Fix a segmentation fault in parallel mode with system_db_hostna

[Yugo Nagata]

Fix a segmentation fault in parallel mode with system_db_hostname is empty

When system_db_hostname is empty, unix domain socket should be used.
However, the directory containing the socket file was't specified in this
case, and the initialization of system DB connection failed. This caused
segmentation fault, when processing a query to system db.

Branch
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V3_1_STABLE

Details
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http://git.postgresql.org/gitweb?p=pgpool2.git;a=commitdiff;h=cbec4c2aa0fc4d0e6f73e38922d76a2d5d3abe80

Modified Files
--------------
doc/pgpool-en.html |    7 +-
doc/pgpool-ja.html |    7 +-
pool_config.c      | 1464 +++++++++++++++++++++++-----------------------------
pool_config.l      |   41 +-
4 files changed, 678 insertions(+), 841 deletions(-)