`manage.bootstrap` gives nonsensical returns

Description of Issue

manage.bootstrap is a nice convenience method for handling the bootstrapping workflow over salt-ssh without actually having to call salt-ssh by hand. A natural next-step in the workflow would be manage.accept followed by setting a highstate on the new minions.

It's pretty clear that it would be nice to combine the whole workflow above into an orchestration. Unfortunately, when called from an orchestration runner, manage.bootstrap always seems to succeed with a "None" result, even under what should ostensibly be error conditions.

          ID: vm_bootstrap
    Function: salt.runner
        Name: manage.bootstrap
      Result: True
     Comment: Runner function 'manage.bootstrap' executed.
     Started: 20:32:55.906305
    Duration: 3427.383 ms
     Changes:   
              ----------
              return:
                  None

Setup

You'll need at least one virtual machine for which you know the IP, ssh username, and ssh password.

The bash scripts below implement the following tests:

• Call manage.bootstrap correctly
• Call manage.bootstrap without any arguments, and no roster
• Call manage.bootstrap with the name of a minion that does not exist in the roster

The outputter reports the same thing each time.

Steps to Reproduce Issue

(Work in progress)

Versions Report

Salt Version:
           Salt: 2019.2.1
 
Dependency Versions:
           cffi: 1.12.3
       cherrypy: Not Installed
       dateutil: 2.8.0
      docker-py: Not Installed
          gitdb: Not Installed
      gitpython: Not Installed
          ioflo: Not Installed
         Jinja2: 2.10.1
        libgit2: Not Installed
        libnacl: Not Installed
       M2Crypto: Not Installed
           Mako: Not Installed
   msgpack-pure: Not Installed
 msgpack-python: 0.6.2
   mysql-python: Not Installed
      pycparser: 2.19
       pycrypto: 2.6.1
   pycryptodome: Not Installed
         pygit2: Not Installed
         Python: 3.6.8 (default, Aug 20 2019, 17:12:48)
   python-gnupg: Not Installed
         PyYAML: 4.2
          PyZMQ: 18.1.0
           RAET: Not Installed
          smmap: Not Installed
        timelib: Not Installed
        Tornado: 4.5.3
            ZMQ: 4.3.2
 
System Versions:
           dist: Ubuntu 18.04 bionic
         locale: UTF-8
        machine: x86_64
        release: 4.15.0-64-generic
         system: Linux
        version: Ubuntu 18.04 bionic

Start at the manage.bootstrap runner entry point and compare its direct salt-ssh behavior with invocation from an orchestration runner. Reproduce the three described calls, including missing arguments and a nonexistent roster minion, and verify that successful and error cases return meaningful results instead of None.