pip.boto saltstack fails

salt-logs.txt

Minion: Ubuntu 16.04.2 LTS, Salt-minion: 2015.8.8 (Beryllium)
Master: Ubuntu 16.04.2 LTS, Salt-master: 2015.8.8 (Beryllium)

From my "core.sls":

```
python-pip:
  pkg:
    - installed
    - refresh: False

boto:
  pip.installed:
    - require:
      - pkg: python-pip
```

Results in this during high state:

```
----------
          ID: boto
    Function: pip.installed
      Result: False
     Comment: An exception occurred in this state: Traceback (most recent call last):
                File "/usr/lib/python2.7/dist-packages/salt/state.py", line 1626, in call
                  **cdata['kwargs'])
                File "/usr/lib/python2.7/dist-packages/salt/loader.py", line 1492, in wrapper
                  return f(*args, **kwargs)
                File "/usr/lib/python2.7/dist-packages/salt/states/pip_state.py", line 592, in installed
                  out = _check_pkg_version_format(pkg)
                File "/usr/lib/python2.7/dist-packages/salt/states/pip_state.py", line 176, in _check_pkg_version_format
                  ret['prefix'] = install_req.req.project_name
              AttributeError: 'Requirement' object has no attribute 'project_name'
     Started: 19:56:30.379232
    Duration: 8.419 ms
     Changes: 
```

pip succeeds directly preceding error:

```
----------
          ID: python-pip
    Function: pkg.installed
      Result: True
     Comment: Package python-pip is already installed
     Started: 19:56:29.711743
    Duration: 5.944 ms
     Changes:   
```