gitweb: use_pathinfo filenames start with /

Generate PATH_INFO URLs in the form project/action/hash_base:/filename
rather than project/action/hash_base:filename (the latter form is still
accepted in input).

This minimal change allows relative navigation to work properly when
viewing HTML files in raw ('blob_plain') mode.

Signed-off-by: Giuseppe Bilotta <giuseppe.bilotta@gmail.com>
Acked-by: Jakub Narebski <jnareb@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

gitweb/gitweb.perl

@@ -734,7 +734,7 @@ (%)
 		# try to put as many parameters as possible in PATH_INFO:
 		#   - project name
 		#   - action
-		#   - hash or hash_base:filename
+		#   - hash or hash_base:/filename
 
 		# When the script is the root DirectoryIndex for the domain,
 		# $href here would be something like http://gitweb.example.com/
@@ -753,11 +753,11 @@ (%)
 			delete $params{'action'};
 		}
 
-		# Finally, we put either hash_base:file_name or hash
+		# Finally, we put either hash_base:/file_name or hash
 		if (defined $params{'hash_base'}) {
 			$href .= "/".esc_url($params{'hash_base'});
 			if (defined $params{'file_name'}) {
-				$href .= ":".esc_url($params{'file_name'});
+				$href .= ":/".esc_url($params{'file_name'});
 				delete $params{'file_name'};
 			}
 			delete $params{'hash'};