added a patch for correctly parse ifname with - char

Hi,
i found three problems:
1)  interface name with - char inside wasn't correctly parsed (for example pppoe-wan) because the script substitutes '-' with '_'. This patch substitute the same cher on /proc/net/dev before interface matching.
2) /proc/net/dev has more spaces as delimiter (variable), changing regexp   with "  *" instead of "  "
3)After two splitting matching row in /proc/net/dev, remaing an initial space that shift the correct column number. Removed initial space