canonicalise emails before checking them against BADMAIL

[jesopo]

closes #773

[jesopo]

maybe worth checking both noncanonicalised and canonicalised?

[jesopo]

<@amdj> jess: #817 leaks memory; you need to strshare_unref() the result before returning.

[spb]

maybe worth checking both noncanonicalised and canonicalised?

Better to canonicalise the badmail entries, IMO.

[jesopo]

no, we get temporary mail providers that use dots in gmail addreses to differentiate addresses and I'd like to badmail *.*.*.*.*@gmail.com but we canonicalise dots out of gmail addresses

[spb]

OK, fair point. In that case you'll have to test both versions.