MINOR: stats: Escape equals sign on socket dump

MINOR: stats: Escape equals sign on socket dump

Greetings,

Was recently working with a stick table storing URL's and one had an
equals sign in it (e.g. 127.0.0.1/f=ab) which made it difficult to
easily split the key and value without a regex.

This patch will change it so that the key looks like
"key=127.0.0.1/f\=ab" instead of "key=127.0.0.1/f=ab".

Not very important given that there are ways to work around it.

Thanks,

- Chad