tun: Don't copy 16byte IPv6 address to 'struct in_addr'

The 'struct tun' curently only has an in_addr (v4-only) member to
store the address of the tun device, so let's not attempt to store
an IPv6 address in it.

FIXME: This entire code needs an overhaul. The assumption that there's
only one address, and only either v6 or v4 is broken to begin with.

Change-Id: If0b626d688841d6e0a3867834f4cb1b70084050e
Fixes: Coverity CID#174278
diff --git a/lib/tun.c b/lib/tun.c
index 6bcc13b..3c293a2 100644
--- a/lib/tun.c
+++ b/lib/tun.c
@@ -396,7 +396,6 @@
 
 #if defined(__linux__)
 	if (addr) {
-		memcpy(&this->addr, addr, sizeof(*addr));
 		memcpy(&ifr.ifr6_addr, addr, sizeof(*addr));
 		if (ioctl(fd, SIOCSIFADDR, (void *) &ifr) < 0) {
 			if (errno != EEXIST) {