**Apache Airflow version**: 1.10.12

**Kubernetes version** : 1.17.9

**Environment**:

- **Cloud provider or hardware configuration**: Azure Kubernetes Service
- **OS** (e.g. from /etc/os-release): Linux
- **Install tools**: Helm chart (/chart in repo) 
- **Others**:

**What happened**:
Pod cannot run since `airflow-cleanup-pods` is not in $PATH
```
Error: failed to start container "airflow-cleanup-pods": Error response from daemon: OCI runtime create failed: container_linux.go:349: starting container process caused "exec: \"airflow-cleanup-pods\": executable file not found in $PATH": unknown
```

**What you expected to happen**: 
Cleanup job pod runs

<!-- What do you think went wrong? -->

**How to reproduce it**:
* Deploy Helm Chart
* Manually trigger `airflow-cleanup ` CronJob 
* See it cannot run since `airflow-cleanup-pods` is not in $PATH
airflow/cli/cli_parser.py
ARG_POOL_NAME = Arg(
    ("pool",),
    metavar='NAME',
    help="Pool name")
ARG_POOL_SLOTS = Arg(
    ("slots",),
    type=int,
    help="Pool slots")
ARG_POOL_DESCRIPTION = Arg(
    ("description",),
    help="Pool description")
ARG_POOL_IMPORT = Arg(
    ("file",),
    metavar="FILEPATH",
    help="Import pools from JSON file")
ARG_POOL_EXPORT = Arg(
    ("file",),
    metavar="FILEPATH",
    help="Export all pools to JSON file")
ARG_VAR = Arg(
    ("key",),
    help="Variable key")
ARG_VAR_VALUE = Arg(
    ("value",),
    metavar='VALUE',
    help="Variable value")
ARG_DEFAULT = Arg(
    ("-d", "--default"),
    metavar="VAL",
    default=None,