The output of 'ansible-galaxy info' was formatting the
'galaxy_info' key with one char per line.
Previously, when building the output string, items in
role_info that had a dict for value, the label for
it's key ('galaxy_info' for ex) was being added to
the text list in addition to being appended. Only
the append is needed.
Also added a unit test in test/units/cli/test_galaxy.py,
but skip it on py3 until galaxy is py3 compatible.
fixes#15177
