RFR [LDAP]: 8062947: Fix exception message to correctly represent LDAP connection failure

[Aleks Efimov]

Hi,

NamingException message is not precise about the cause of LDAP 
connection failure, i.e. in case of LDAP connection closure the 
NamingException with misleading message is thrown:
"LDAP response read timed out, timeout used:-1ms.":
https://bugs.openjdk.java.net/browse/JDK-8062947

The following fix tries to tackle this issue:
http://cr.openjdk.java.net/~aefimov/8062947/00

Also, while we're here we can remove the commented debug code blocks in 
Connection class

LDAP regression and javax.naming JCK tests are green - no failures

With Best Regards,
Aleksei