[pgpool-hackers: 608] Change default value for log_line_prefix

[Tatsuo Ishii]

Hi Usama,

I have changed the default value for new parameter "log_line_prefix"
from empty string to '%t: pid %p: '. For pre-3.4, log_timestamp is on
and the default log line is something like:

2014-10-12 20:01:57: pid 23973: LOG:  find_primary_node: primary node id is 0

With empty string with log_line_prefix, the log is something like:

LOG:  find_primary_node: primary node id is 0

which may bring surprise to users. Also the log format change broke
one of regression test (0007.dbredirect). With the new default value
for log_line_prefix, all concerns above are resolved.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp