CONNECTION FAILURES USING THREAD POOL

ANALYSIS:
=========
Status variable 'Aborted_connects' is not being incremented
for every unsuccessful connection attempt via thread pool
plugin.

Status variable 'Aborted_connects' keeps the count of
failed attempts to connect to the MySQL server.

Error information was reported in case of failed connection
attempts using thread pool but the status variable
'Aborted_connects' was not being incremented.

FIX:
====
1. 'Aborted_connects' now keeps track of unsuccessful
   connection attempt via thread pool plugin.
2. Amount of information logged in the error log for failed
   connection attempts using thread pool has been reduced.