gitweb: Don't escape attributes in CGI.pm HTML methods

gitweb: Don't escape attributes in CGI.pm HTML methods

There is no need to escape HTML tag's attributes in CGI.pm
HTML methods (like CGI::a()), because CGI.pm does attribute
escaping automatically.

Explanation:
  $cgi->a({ ... -attribute => atribute_value }, tag_contents)
is translated to
  <a ... attribute="attribute_value">tag_contents</a>
The rules for escaping attribute values (which are string contents) are
different. For example you have to take care about escaping embedded '"'
and "'" characters; CGI::a() does that for us automatically.

CGI::a() cannot HTML escape tag contents automatically; we might want to
write
  <a href="URL">some <b>bold</b> text</a>
for example. So we have to esc_html (or esc_path) if needed.

Signed-off-by: Jakub Narebski <jnareb@gmail.com>