elasticsearch libraries not found after installing elasticsearch-py and reloading modules

Description of Issue

The following error happens after installing elasticsearch-py with reload_modules: true

'elasticsearch' __virtual__ returned False: Cannot load module elasticsearch: elasticsearch libraries not found

Setup

formulas.installed.elastic:
  pip.installed:
    - name: elasticsearch>=6.0.0,<7.0.0
    - reload_modules: true

formulas.elastic.pipeline:
  module.run:
  - name: elasticsearch.pipeline_create
  - id: pipeline
  - body: {...}

Steps to Reproduce Issue

1. Run the above formulas
2. Error running the module

Restarting the minion fixes the issue.

Versions Report

# salt --versions-report
Salt Version:
           Salt: 2019.2.0

Dependency Versions:
cffi: 1.12.3
cherrypy: Not Installed
dateutil: 2.5.3
docker-py: 4.0.2
gitdb: 2.0.0
gitpython: 2.1.1
ioflo: Not Installed
Jinja2: 2.9.4
libgit2: Not Installed
libnacl: Not Installed
M2Crypto: Not Installed
Mako: Not Installed
msgpack-pure: Not Installed
msgpack-python: 0.4.8
mysql-python: Not Installed
pycparser: 2.19
pycrypto: 2.6.1
pycryptodome: Not Installed
pygit2: Not Installed
Python: 2.7.13 (default, Sep 26 2018, 18:42:22)
python-gnupg: Not Installed
PyYAML: 3.12
PyZMQ: 16.0.2
RAET: Not Installed
smmap: 2.0.1
timelib: Not Installed
Tornado: 4.4.3
ZMQ: 4.2.1

System Versions:
dist: debian 9.6
locale: ANSI_X3.4-1968
machine: x86_64
release: 4.9.0-8-amd64
system: Linux
version: debian 9.6

Start by reproducing the pip.installed setup with reload_modules: true, then run elasticsearch.pipeline_create and inspect the module-loading path for the Elasticsearch integration. Done means the module can find the newly installed elasticsearch-py library and create the pipeline without restarting the minion.