Fix for issue #93 - cleanup error hiding exception details

[tlynn]

This is the suggested fix from the first comment on issue #93, with a test demonstrating the problem.

[tlynn]

Hmmm, looks like I need to provide Py 3 compatibility.

[tlynn]

Ping! Would you mind looking at this, please?

[davidism]

I'm not clear how this issue can happen. The test is very complex, and does not seem to do anything about host not having a sock attribute. The following code does not seem to have any issue. If you still have an issue, please open a new issue with a minimal reproducible example and clear description.

from flask import Flask
from flask_mail import Mail, Message

app = Flask(__name__)
app.config.update({
    "MAIL_HOST": "127.0.0.1",
    "MAIL_PORT": 1025,
})
mail = Mail(app)

with app.app_context():
    with mail.connect() as c:
        c.send(Message("test", sender="test", recipients=["test"]))