Add PING_TYPE_INSERT

To detect a failure like mysqld can accept a new connection and can respond
a simple select queries, but cannot respond insert/update/delete queries.

In particular, I want to detect hardware trouble (disk failure or RAID
controller failure) and perform fail over automatically.
Reformat source code by perltidy -i=2
Merge branch 'feature/ping-insert' of https://github.com/hirose31/mha4mysql-manager
If mysqld accepts queries but hangs on updates
(i.e. RAID controller failure), ping_type=insert causes
duplicate advisory lock failure. This patch prevents the
failure by not acquiring an advisory lock when
checking connections.
Formatting (perltidy -i=2)
Fixing test cases
Merge pull request #41 from hirose31/feature/ping-insert

Add PING_TYPE_INSERT
Merge branch 'master' of https://github.com/yoshinorim/mha4mysql-manager