* testenv/README: Added description for new EnvironmentVariable hook
* testenv/conf/environment_variable.py: Added implementation of
EnvironmentVariable hook
* testenv/test/base_test.py: Modified exec_wget() to enable use of
EnvironmentVariable hook
Added new test hook called EnvironmentVariables, for defining environment
variables when wget is executed in tests. This is handy for testing
environment variables, which are accepted by wget.
Signed-off-by: Tomas Hozza <thozza@redhat.com>
