css-url.c (get_uri_string): Fix regression from 8e6de1fb5

Solves the issue discovered by Gabriel Somlo and reported in the ml thread
"Regression in git master branch (commit 8e6de1fb5ff0ca0c749da7db634a1b1e3a1215a2)"
Fix make distcheck for Python tests
Minor optimizations of Python tests
add TLSv1_1 and TLSv1_2 to --secure-protocol