**Apache Airflow version**:

2.1.0

**Environment**:

- self hosted docker-compose based stack

**What happened**:

Using JDBCOperator if the sql result in an error we got only 
```
[2021-06-21 11:05:55,377] {local_task_job.py:151} INFO - Task exited with return code 1
```

Before upgrading from 2.0.1 we got error details in logs:
```
jaydebeapi.DatabaseError: java.sql.SQLException:... [MapR][DrillJDBCDriver](500165) Query execution error. Details: VALIDATION ERROR:...
``` 

**What you expected to happen**:

See `SQLException` in logs

**How to reproduce it**:

Perform a generic SQL task with broken SQL.

**Anything else we need to know**:

I think is somehow related to https://github.com/apache/airflow/commit/abcd48731303d9e141bdc94acc2db46d73ccbe12#diff-4fd3febb74d94b2953bf5e9b4a981b617949195f83d96f4a589c3078085959b7R202 
airflow/models/taskinstance.py
if conf.has_option('email', key):
                    path = conf.get('email', key)
                    with open(path) as f:
                        content = f.read()
                return jinja_env.from_string(content).render(**jinja_context)
            subject = render('subject_template', default_subject)
            html_content = render('html_content_template', default_html_content)
            html_content_err = render('html_content_template', default_html_content_err)
        return subject, html_content, html_content_err
    def email_alert(self, exception):
        """Send alert email with exception information."""
        subject, html_content, html_content_err = self.get_email_subject_content(exception)
        try:
            send_email(self.task.email, subject, html_content)
        except Exception:
            send_email(self.task.email, subject, html_content_err)
    def set_duration(self) -> None:
        """Set TI duration"""
        if self.end_date and self.start_date:
            self.duration = (self.end_date - self.start_date).total_seconds()
        else:
            self.duration = None
        self.log.debug("Task Duration set to %s", self.duration)
    @provide_session
    def xcom_push(
        self,
        key: str,
        value: Any,
        execution_date: Optional[datetime] = None,
        session: Session = None,