Repository: apache/airflow

Issue:
[AIRFLOW-3014] Fix multiple alembic heads
Make sure you have checked _all_ steps below.

### Jira

- [ ] My PR addresses the following [Airflow Jira](https://issues.apache.org/jira/browse/AIRFLOW/) issues and references them in the PR title. For example, "\[AIRFLOW-XXX\] My Airflow PR"
  - https://issues.apache.org/jira/browse/AIRFLOW-6224
  - In case you are fixing a typo in the documentation you can prepend your commit with \[AIRFLOW-XXX\], code changes always need a Jira issue.
  - In case you are proposing a fundamental code change, you need to create an Airflow Improvement Proposal ([AIP](https://cwiki.apache.org/confluence/display/AIRFLOW/Airflow+Improvements+Proposals)).
  - In case you are adding a dependency, check if the license complies with the [ASF 3rd Party License Policy](https://www.apache.org/legal/resolved.html#category-x).

### Description

- [ ] Here are some details about my PR, including screenshots of any UI changes:

### Tests

- [ ] My PR adds the following unit tests __OR__ does not need testing for this extremely good reason:

### Commits

- [ ] My commits all reference Jira issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "[How to write a good git commit message](http://chris.beams.io/posts/git-commit/)":
  1. Subject is separated from body by a blank line
  1. Subject is limited to 50 characters (not including Jira issue reference)
  1. Subject does not end with a period
  1. Subject uses the imperative mood ("add", not "adding")
  1. Body wraps at 72 characters
  1. Body explains "what" and "why", not "how"

### Documentation

- [ ] In case of new functionality, my PR adds documentation that describes how to use it.
  - All the public functions and the classes in the PR contain docstrings that explain what it does
  - If you implement backwards incompatible changes, please leave a note in the [Updating.md](https://github.com/apache/airflow/blob/master/UPDATING.md) so we can assign it to a appropriate release



Discussion:

Resolving patch:
diff --git a/airflow/migrations/versions/c1840b4bcf1a_increase_length_of_password_column_in_.py b/airflow/migrations/versions/c1840b4bcf1a_increase_length_of_password_column_in_.py
deleted file mode 100644
--- a/airflow/migrations/versions/c1840b4bcf1a_increase_length_of_password_column_in_.py
+++ /dev/null
@@ -1,50 +0,0 @@
-#
-# Licensed to the Apache Software Foundation (ASF) under one
-# or more contributor license agreements.  See the NOTICE file
-# distributed with this work for additional information
-# regarding copyright ownership.  The ASF licenses this file
-# to you under the Apache License, Version 2.0 (the
-# "License"); you may not use this file except in compliance
-# with the License.  You may obtain a copy of the License at
-#
-#   http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing,
-# software distributed under the License is distributed on an
-# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-# KIND, either express or implied.  See the License for the
-# specific language governing permissions and limitations
-# under the License.
-
-"""Increase length of password column in connection table
-
-Revision ID: c1840b4bcf1a
-Revises: 004c1210f153
-Create Date: 2019-10-02 16:56:54.865550
-
-"""
-
-import sqlalchemy as sa
-from alembic import op
-
-# revision identifiers, used by Alembic.
-revision = 'c1840b4bcf1a'
-down_revision = '004c1210f153'
-branch_labels = None
-depends_on = None
-
-
-def upgrade():
-    conn = op.get_bind()
-    if conn.dialect.name == 'sqlite':
-        # SQLite does not allow column modifications so we need to skip this migration
-        return
-
-    op.alter_column(table_name='connection',
-                    column_name='password',
-                    type_=sa.String(length=5000))
-
-
-def downgrade():
-    # Can't be undone
-    pass


Test patch: