make_description: add an option for URLs from reported_to

The option causes that the description text will contain all URLs found
in reported_to file.

For reported_to line:
Bugzilla: URL=http://bugzilla.redhat.com/1000000

the following line will be included in the description:
Bugzilla: http://bugzilla.redhat.com/1000000

Related to rhbz#1036585

Signed-off-by: Jakub Filak <jfilak@redhat.com>
add unit test for make_description (SHOW_URLS)

Related to rhbz#1036585

Signed-off-by: Jakub Filak <jfilak@redhat.com>