Remove extra const qualifiers.

Some function declared parameters like this:
	int f(const char * const s)
Where appropriate, I changed to
	int f(const char *s)

The second const is a qualifier on the pointer itself; i.e., the value
of s may not be changed (may not be made to point to anything else)
within the function. This is probably not what was intended. The first
const is what prevents modifying things referenced through s.

libnetutil/netutil.cc

@@ -1641,7 +1641,7 @@ struct sys_route *getsysroutes(int *howmany, char *errstr, size_t errstrlen) {
  * localhost. (eg: the address is something like 127.x.x.x, the address
  * matches one of the local network interfaces' address, etc).
  * Returns 1 if the address is thought to be localhost and 0 otherwise */
-int islocalhost(const struct sockaddr_storage *const ss) {
+int islocalhost(const struct sockaddr_storage *ss) {
   char dev[128];
   struct sockaddr_in *sin = NULL;
   struct sockaddr_in6 *sin6 = NULL;