Escape all remaining reserved chars in direct_fog_url

From URI::Parser
URI regexp pattern for rel_segment
      RESERVED = ";/?:@&=+$,\\[\\]"
      rel_segment   = ( unreserved | escaped |
                          ";" | "@" | "&" | "=" | "+" |
                          "$" | "," )
Hence, '?:[]' need to be escaped for the URI path to not throw exceptions on parsing.