Fix release notes' style and add missing notes
Fix names in release notes
Fix to ignore a harmless error code when executing ifconfig command

When executing command such as ifconfig or ping by execv() in a forked
child proess, wait() can fails with an error code ECHILD, although the
process exists exactly, if SIGCHLD is set to SIG_IGN in Linux. We should
ignore this and not treat as failure of the command.
Add undocumented "-j" option to the script comment.
Fix unwanted JDBC regression test failure.

JDBC tests mixes SELECT and DML, an it causes random regression
failures when tested in streaming replication mode. This is due to
streaming replication lag. To fix the problem, set number of DB nodes
to 1 when operated in the streaming replication mode.
Fix to prevent regression test failures on slow machines.

wait_for_pgpool_startup and wait_for_pgpool_reload returns after 20
times try regardless the task has succeeded or not, which gives
confusions to rest of the script. The fix is, just adding nap time
between each retry. Because it's unlikely that pgpool takes over 20
seconds before successfully starting the operation.