Remove license text from the files that are not essential.

Remove the license text from files inside docs, examples and selftest,
to keep the license text only in relevant parts of the project.

References:

* https://fedoraproject.org/wiki/Packaging:LicensingGuidelines
* https://www.gnu.org/licenses/gpl-howto.html

Signed-off-by: Rudá Moura <rmoura@redhat.com>
Merge pull request #269 from ruda/remove_license_non_essential

Remove license text from the files that are not essential.
.travis.yml: Return apt-get update

Since we have to install extra packages in the VM, some
of which might have been moved/updated, apt-get update
turns out necessary.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
Merge pull request #278 from lmr/fix-travis-apt-get

.travis.yml: Return apt-get update
avocado.test: Support params passing to DropinTests

This patch injects all params as env variables to
DropinTests. This is very useful for multiplexing
these tests.

Additionally the env_variables.sh example test was
adjusted to print CUSTOM_VARIABLE, which can be used
in selftest.

Signed-off-by: Lukáš Doktor <ldoktor@redhat.com>