Correctly ignore south migrations

Signed-off-by: Michal Čihař <michal@cihar.com>
Revert "Simplify setup by sharing common settings in global environment"

This reverts commit 1031bcb373b03736518d8ad29488c4e6bec63d15.

It really does not work as travis ignores global variables which are
used in matrix as well.

Signed-off-by: Michal Čihař <michal@cihar.com>
Do not explicitely set tests to run

We can rely on Django to run all our tests by default.

Signed-off-by: Michal Čihař <michal@cihar.com>
Default to sqlite database for tests if not specified

This allows us to simplify travis setup.

Signed-off-by: Michal Čihař <michal@cihar.com>
Whitespace cleanup

Signed-off-by: Michal Čihař <michal@cihar.com>