Don't throw exceptions for (p)connect calls.

When Redis::(p)connect() is called on a newly created Redis instance that will always cause an exception to be thrown. The connect code will actually try and cancel the
exception but this is problematic when you are using tools like APM (pecl.php.net/apm) which hook into the exception handler: it will already have handled it. This change simply stops the connect from throwing exceptions for that situation.

Relevant issues: #183, #196, #250 (we reported this one)