Fix 'tox -e cover'

'tox -e cover' fails as --coverage-package-name option for 'testr' is
not recognized. A work-around proposed by Infra team (see
https://bugs.launchpad.net/neutron/+bug/1454772) is to replace 'testr'
with 'test'.

This patch implements this change and adds the cover/ directory to
.gitignore.

Change-Id: I659445ea479ea80a4f21d6ebca896abb4fb104f2
Closes-Bug: #1703177

.gitignore

@@ -26,6 +26,7 @@ pip-log.txt
 .tox
 nosetests.xml
 .testrepository
+cover
 
 # Translations
 *.mo
@@ -48,4 +49,4 @@ ChangeLog
 
 # Editors
 *~
-.*.swp
+.*.swp

tox.ini

@@ -19,7 +19,7 @@ commands = flake8
 commands = {posargs}
 
 [testenv:cover]
-commands = python setup.py testr --coverage --coverage-package-name=os_net_config --testr-args='{posargs}'
+commands = python setup.py test --coverage --coverage-package-name=os_net_config --testr-args='{posargs}'
 
 [testenv:docs]
 commands = python setup.py build_sphinx