salt-call option --states-dir is being ignored

Description of Issue

Option --states-dir of salt-call is ignored, as the result state files is not being located. As far as I can see in code relevant configuration option is getting initialized but not used.

Setup

Directory structure:

[root@troll _salt-call_bug]# tree
.
└── states
    └── test.sls

[root@troll _salt-call_bug]# ls -laR
.:
total 4
drwxr-xr-x  3 root root  43 Mar 28 11:43 .
drwxr-xr-x 10 root root 191 Mar 28 11:42 ..
-rw-r--r--  1 root root   7 Mar 28 11:43 .python-version
drwxr-xr-x  2 root root  22 Mar 28 11:45 states

./states:
total 4
drwxr-xr-x 2 root root 22 Mar 28 11:45 .
drwxr-xr-x 3 root root 43 Mar 28 11:43 ..
-rw-r--r-- 1 root root 51 Mar 28 11:45 test.sls

State file:

aaa:
  test.show_notification:
    - text: works !

Steps to Reproduce Issue

salt-call --local --file-root=states state.apply test is succesful
salt-call --local --states-dir=states state.apply test fails with:

local:
    Data failed to compile:
----------
    No matching sls found for 'test' in env 'base'

Versions Report

Salt Version:
           Salt: 3000
 
Dependency Versions:
           cffi: Not Installed
       cherrypy: Not Installed
       dateutil: Not Installed
      docker-py: Not Installed
          gitdb: Not Installed
      gitpython: Not Installed
         Jinja2: 2.11.1
        libgit2: Not Installed
       M2Crypto: Not Installed
           Mako: Not Installed
   msgpack-pure: Not Installed
 msgpack-python: 0.6.2
   mysql-python: Not Installed
      pycparser: Not Installed
       pycrypto: 2.6.1
   pycryptodome: Not Installed
         pygit2: Not Installed
         Python: 3.6.10 (default, Mar 28 2020, 09:48:49)
   python-gnupg: Not Installed
         PyYAML: 3.13
          PyZMQ: 19.0.0
          smmap: Not Installed
        timelib: Not Installed
        Tornado: 4.5.3
            ZMQ: 4.3.2
 
System Versions:
           dist: centos 8.1.1911 Core
         locale: UTF-8
        machine: x86_64
        release: 4.18.0-147.5.1.el8_1.x86_64
         system: Linux
        version: CentOS Linux 8.1.1911 Core

Start by reproducing the two commands in the issue: compare salt-call --local --file-root=states state.apply test with the failing --states-dir variant. Trace how salt-call initializes and consumes these options, then add coverage showing that --states-dir locates states/test.sls and the command succeeds without --file-root.