Don't try to `listdir` on a non existing `jid_root`.

Additionally, removed unnecessary brackets on logging messages and some PEP-8 formatting.
Use outputters in runners/manage.py.
Add a silent outputter.

This allows me to call a runner and only get the return data back.
Fix a misplaced `continue` on the grains matching logic which caused a traceback.

```
[21:18:46,004 [salt.utils.minions                          :200 ][ERROR   ] Failed matching available minions with grain pattern: planets:saturn
Traceback (most recent call last):
  File "/home/ubuntu/salt/salt/utils/minions.py", line 197, in check_minions
      }[expr_form](expr)
        File "/home/ubuntu/salt/salt/utils/minions.py", line 119, in _check_grain_minions
    str(match.lower()),
    AttributeError: 'list' object has no attribute 'lower'
```
Remove left over code.
Merge branch 'develop' of github.com:saltstack/salt into hotfix/fix-travis-again
Moved groups assignment out of useradd to avoid errors when the group is the same as the default user group
Merge pull request #4068 from s0undt3ch/hotfix/fix-travis-again

Don't try to `listdir` on a non existing `jid_root`.
Merge pull request #4076 from torhve/develop

Use a default for multiprocessing if not set. This fixes #4075
check whether a usergroup is set explicitly as part of the groups parameter and set it as default group on systems with usergroups enabled
added try..except around file open call as this will fail on some systems.
In such cases it is assumed usergroups are not enabled.
* some cleanup
* pep8 fix
Added show_diff kwarg to file.managed.

This can be set on a per-file basis so that potentially-sensitive
content can be omitted from logs.
fix #4065
fix pep8
bump Windows installer version
Add link to 32bit Salt Windows installer
Merge pull request #4081 from UtahDave/develop

bump Windows installer version
Merge pull request #4082 from UtahDave/develop

Add link to 32bit Salt Windows installer
Add link to 64bit Windows installer