tests: fix warnings

While I don't see -Werror being used on tests anytime soon, there's no
reason to keep the warnings in tests unfixed.

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/tests/bgp_mp_attr_test.c b/tests/bgp_mp_attr_test.c
index 5f0e733..d649e14 100644
--- a/tests/bgp_mp_attr_test.c
+++ b/tests/bgp_mp_attr_test.c
@@ -545,7 +545,7 @@
     return -1;
   
   peer = peer_create_accept (bgp);
-  peer->host = "foo";
+  peer->host = (char *)"foo";
   
   for (i = AFI_IP; i < AFI_MAX; i++)
     for (j = SAFI_UNICAST; j < SAFI_MAX; j++)