warnings about unversioned tags when used with mq

[reece]

trafficstars

mq generates temporary tags for which no version exists. This results in errors like the following:

$ hg qnew test-config
$ python setup.py test
/home/reece/projects/biocommons/biocommons.seqrepo/.eggs/setuptools_scm-3.1.0-py3.6.egg/setuptools_scm/version.py:92: UserWarning: tag 'qbase' no version found
  warnings.warn("tag %r no version found" % (tag,))
/home/reece/projects/biocommons/biocommons.seqrepo/.eggs/setuptools_scm-3.1.0-py3.6.egg/setuptools_scm/version.py:92: UserWarning: tag 'qtip' no version found
  warnings.warn("tag %r no version found" % (tag,))
/home/reece/projects/biocommons/biocommons.seqrepo/.eggs/setuptools_scm-3.1.0-py3.6.egg/setuptools_scm/version.py:92: UserWarning: tag 'test-config' no version found
  warnings.warn("tag %r no version found" % (tag,))
running pytest
running egg_info
...

This issue may be related to #303.