sockaddr: Turn FIXME comment into XXX

The LGTM service constantly annoys me with this alert, which in fact
isn't actually a thing that's broken, because the function in question
is just slower than it could be.

This is going to be addressed at some point[1] but it's not something
critical and since "FIXME" is the wrong label anyway, let's get rid of
that annoying alert.

[1]: #25

Signed-off-by: aszlig <[email protected]>

src/sockaddr.cc

@@ -244,7 +244,7 @@ bool SockAddr::operator==(const SockAddr &other) const
 
 std::size_t SockAddr::get_hash(void) const
 {
-    // FIXME: This function is pretty slow and dumb, but at least accurate.
+    // XXX: This function is pretty slow and dumb, but at least accurate.
     std::ostringstream hashprep;
     hashprep << this->ss_family;